American and Russian scientists secretly worked together for about 17 years to remove hundreds of kilos of plutonium and highly enriched uranium from an abandoned nuclear test site in Kazakhstan, a report says.

The nuclear material left from Soviet era was enough to construct several nuclear weapons, the New York Times said Saturday, citing a report released last week by the Belfer Center for Science and International Affairs at Harvard.
The cleanup operation cost the US and Russia $150 million, with the US government paying the larger part, the report said.
Siegfried S. Hecker, a former director of the Los Alamos National Laboratory who first visited the test site in 1998, said the site contained nuclear material “in reasonably concentrated form, easily picked up, completely open to whoever wants to come.”

The cleanup operation began by Russian and American scientists, without the “elaborate, negotiated state-to-state agreements of the kind used for arms control during the cold war,” according to the report.
In 1999, on the margins of an international nonproliferation conference, the US agreed to finance the cleanup effort, Russia agreed to provide information and scientists, and Kazakhstan agreed to do the fieldwork.
The Time said, when one of its reporters visited the site in 2011, the effort was shrouded by a heavy veil of secrecy.
In October 2012, the cleanup was completed.