“U.S. will not tolerate any actions by Iran that risk new arms race and threaten the credibility of the international community and our collective security,” U.S. President Barack Obama stated at the joint press conference with his Russian counterpart Dmitry Medvedev after signing the the START treaty, msnbc website reports.

According to Obama, Washington will work hard for the United Nations Security Council to impose tougher sanctions on Iran.

“We will not tolerate actions that flout the Nuclear Proliferation Treaty. My expectation is that we are going to be able to secure strong, tough sanctions on Iran this spring,” Obama stressed.

“Tehran has not responded to many constructive proposals the international community offers, and it's possible the United Nations Security Council will have to take up the issue,” Medvedev said.