Russia completes annexation of Crimea: Russian President Vladimir Putin on Friday signed legislation to complete the annexation of Crimea, just hours after the first signs emerged in Russia of the bite from U.S. sanctions.

Russian forces used at least four armored vehicles to break into an air base here, seizing control of one of the last Ukrainian military outposts in Crimea.

After an hours-long tense standoff between Russian and Ukrainian forces, gunfire and explosions could be heard as the vehicles broke down the gate at the air base located just outside Sevastopol. It appeared that at least two people had been wounded, and were taken away in ambulances.

The assault on the base in Belbek came as an ominous mood was settling over the town. Russians and their many supporters want the Ukrainian forces to join their side or leave Crimea. Signs calling for the death of the base commander had been posted outside the installation.

Russian President Vladimir Putin completed his annexation of Crimea on Friday, signing a law making the peninsula part of Russia. Meanwhile, Ukraine moved closer to Europe, signing a political association agreement with the EU at a summit.

Saturday afternoon the Russians delivered an ultimatum demanding that the Ukrainians surrender their weapons and abandon the base. After several hours, they forced their way in.

“Why did you shoot?” one Ukrainian angrily demanded. The assault brought on a torrent of shouting but no panic.

Yuli Mamchur, the Ukrainian base commander, said he had ordered his men not to resist to avoid casualties.

“We have done everything we could,” Mamchur told his men after the Russians took over the base. “You acted with honor. There is nothing we should be ashamed of.”

Prior to the Russians storming the base, Mamchur had ordered his men to their stations. But those at the gate were armed only with sticks.

Ukrainian troops spent the afternoon burning documents and toasting with champagne two lieutenants who were married on what may be the base’s last day in Ukrainian hands.

Late in the afternoon, a Ukrainian officer parleyed with a Russian officer at the front gate. The Russian said the Ukrainians need to leave because this is now Russian territory.

The discussion went back and forth. The Ukrainian asked for documents proving that it is now Russian territory.

“When was the last time you watched television?” the Russian replied.

After the discussion broke up, the Russian armored vehicles suddenly appeared.

Although Russia on Friday welcomed Crimea with deep-booming fireworks that celebrated the territorial expansion of Russia at Ukraine’s expense, Ukraine’s leaders reiterated Saturday that they do not recognize the annexation.

The standoff at the base came as Russia said it would not allow access to Crimea for international monitors who are being dispatched to Ukraine.

The monitors will be deployed as part of an Organization for Security and Cooperation in Europe mission after Russia late Friday dropped its opposition. An initial force could be dispatched as soon as Saturday evening, and up to 400 monitors will ultimately deploy across the country, including in Ukraine’s volatile south and east. Clashes in those areas in recent weeks between pro-Russian and pro-Ukrainian demonstrators have turned deadly.

Polish Foreign Minister Radoslaw Sikorski said in an interview published Saturday in the Polish newspaper Gazeta Wyborcza that he believes Russia was actively trying to undermine Ukrainian authority in eastern Ukraine, a charge Moscow has denied.

Pro-Russian rallies were held in the eastern Ukrainian cities of Donetsk and Kharkiv Saturday, but according to Russian news reports, they did not attract large crowds. No disruptions were immediately reported.

On Friday, Russian President Vladimir Putin, defiant in the face of growing Western pressure, signed a treaty of accession moments after it was ratified by the upper house of parliament. The deal gives the Crimean Peninsula to Russia, but it has pushed a diminished Ukraine further toward the West.

In Brussels on Friday, Ukraine’s leaders signed an agreement committing the country to closer ties with the European Union and said they had been promised more than $1 billion in additional economic aid. Russia, meanwhile, has become the target of expanded sanctions due to the Crimea situation.

The E.U., following the lead of the United States, added a dozen names Friday to its list of Russian officials subject to visa and financial restrictions. But efforts by eastern members of the E.U. to pursue much tougher measures were rebuffed by leaders of bigger countries worried about the consequences for their own economies.

The Russian Foreign Ministry on Saturday called Europe’s moves “divorced from reality,” and said Russia reserves the right to respond. No immediate action against Europe was announced, however.

With targeted Western sanctions, and with the Fitch rating agency joining Standard & Poor’s in downgrading Russia’s credit score Friday, the economy seemed poised to begin wobbling. But some of the leading indicators have remained steady.

The ruble, which dropped sharply as the Crimean crisis began, fluctuated through the past week and ended up in a slightly stronger position than it had been in on Monday, at 36.4 to the U.S. dollar.

The Moscow stock exchange dropped nearly 3 percent Friday, after the expanded sanctions lists and the credit downgrades were announced, but it still ended up for the week, by more than 3 percent.

The price of oil, which is a major revenue source for Russia, spiked at the beginning of the crisis, dropped back down, and toward the end of the week rose steadily upward again. Brent Crude, a major benchmark, posted gains of a dollar a barrel from Wednesday to Friday, when it went for just over $107. Any increase is good news for the Russian economy

Politicians in Moscow have joked about the sanctions. But the measures have begun to show some bite, and several hundred thousand Russians could be feeling their effect.

MasterCard and Visa stopped handling transactions for Bank Rossiya, which was placed on the U.S. sanctions list Thursday by President Obama, and for the much smaller SMP Bank, which is owned by two brothers, Arkady and Boris Rotenberg, who are also on the U.S. list. The Rotenbergs are old friends of Putin’s and have grown rich since he came to power.

Also blocked was the credit card business of several small banks that rely on the two bigger ones to handle transactions.

“It will not have a huge effect,” said Anton Soroko, a bank analyst in Moscow. Bank Rossiya, the country’s 15th-largest bank, has about 470,000 individual clients. Most of them have direct deposit for their salaries and use their cards only to withdraw cash from ATMs — a procedure that is still possible, according to Natalia Romanova, editor of the Web site

It remains unusual, she said, for Russians to use credit cards for point-of-sale purchases or to make purchases online.

Yet the news of the suspended transactions caught people’s attention. Putin said he would open an account in Bank Rossiya on Monday and have his salary deposited there.

At a meeting of Russia’s national security council, he joked about not associating too closely with some of his aides who are on the U.S. and E.U. lists. He said Russia, for now, should not retaliate any further than the entry bans for nine U.S. officials it announced Thursday.

But later in the afternoon, the talk grew more menacing. Russia will not let further sanctions go unanswered, said Putin’s spokesman, Dmitry Peskov.

“We will react every time, and we react based on mutuality. We have responded to the first sanctions, and now we will respond” to further sanctions, he said. “They will not go unnoticed.”

The Foreign Ministry promised a stiff response to the United States.

“The U.S. administration decision announced on March 20 to expand the list of sanctions against Russian officials, parliamentarians and businessmen as a punishment for Crimea’s reunification with Russia causes disappointment and regret,” said a statement attributed to Alexander Lukashevich, the ministry’s press secretary. “We are certain to respond toughly as already happened on more than one occasion earlier with respect to earlier sanctions.”

Alexei Pushkov, head of the foreign affairs committee of the Duma, or lower house of parliament, tweeted Friday: “Economic sanctions make sense when their goal is to prevent something. The reunification with Crimea is already a fact. There’s nothing they can prevent. What’s the point?”

Ukraine’s leaders, stung by the loss of Crimea and facing dire problems at home, hope to capitalize on Western support. The interim prime minister, Arseniy Yatsenyuk, signed an agreement at the Brussels E.U. summit that could lead to broader cooperation.

It came four months to the day after the ousted president of Ukraine, Viktor Yanukovych, spurned a deal with the E.U. in favor of an arrangement with Russia, provoking the long-lasting protest that eventually brought him down.

Ukraine is still a significant way from formally joining the 28-nation E.U. bloc, and such a move would probably draw a furious response from Moscow. But Yatsenyuk said he believed that Friday’s signing of a political association agreement marked a major push in that direction.

“We want to be a part of the big European family, and this is the first tremendous step in order to achieve for Ukraine its ultimate goal, as a full-fledged member,” he said.

The signing of the deal with Ukraine overshadowed, for a day, Europe’s continuing struggles over how to penalize Moscow for its annexation of Crimea.

Some members, particularly those in Eastern Europe, have pushed for tough sanctions, fearing that without a stern response from the West, Russia will be emboldened to reach for more territory. But other European nations, including E.U. heavyweights such as Germany, have deep economic ties with Russia and are reluctant to push too hard. About a third of Europe’s natural gas comes from Russian sources.

Without unanimous support for broad financial sanctions, the E.U. focused on more modest steps.

On Friday, it announced the addition of 12 individuals to its sanctions list, which began with 21 names earlier in the week. The new names appeared to be part of an effort to coordinate strategy with the United States and included several Putin aides and officials who have been sanctioned by Washington. Among them were Dmitry Rogozin, a deputy prime minister.

The list also included Dmitry Kiselyov, a Russian news anchor who was recently chosen to head the Kremlin’s new information agency, Russia Today. Kiselyov responded to American criticism of the Crimean referendum Sunday by warning that Russia was capable of turning the United States into “radioactive ashes.”

Notably, Europe did not go after Russian oligarchs or banks, as the United States did on Thursday. But European leaders said they have prepared additional penalties that would be triggered if Putin makes a play for other parts of Ukraine.

“If there’s further destabilization in Ukraine, then there should be further, wide-ranging measures taken,” said British Prime Minister David Cameron, who did not give specifics.

British Prime Minister David Cameron said the best rebuke to Russia would be a strong Ukraine, a sentiment that other European leaders echoed. The E.U. also sought on Friday to bolster other potentially vulnerable nations in Russia’s shadow, signaling that the bloc would sign deals to tighten relations with Georgia and Moldova !!!