“We have heard that Netanyahu came with a list and concrete evidence showing that Russians are helping the Iranians to develop a bomb,” said a source close to the Russian defence minister last week.

“That is why it was kept secret. The point is not to embarrass Moscow, rather to spur it into action.”…

“There has been Russian help. It is not the government, it is individuals, at least one helping Iran on weaponisation activities and it is worrisome,” said David Albright, a former weapons inspector who is president of the Institute for Science and International Security.

However, Israeli officials insist that any Russian scientists working in Iran could do so only with official approval.