The United Nations has reimposed an arms embargo and other sanctions on Iran over its nuclear program after European powers triggered the process, prompting Tehran to threaten a harsh response.

Britain, France and Germany initiated the return of sanctions on Iran at the U.N. Security Council over accusations it had violated a 2015 deal that aimed to stop it from developing a nuclear bomb. Iran denies seeking nuclear weapons.

The end of the decadelong nuclear deal originally agreed by Iran, Britain, Germany, France, the United States, Russia and China is likely to exacerbate tensions in the Middle East, just months after Israel and the U.S. bombed Iranian nuclear sites.

U.N. sanctions imposed by the Security Council in resolutions adopted between 2006 and 2010 were reinstated at 8 p.m. EDT on Saturday (12 a.m. GMT on Sunday). Attempts to delay the return of all sanctions on Iran failed on the sidelines of the annual gathering of world leaders at the U.N. this week.

"We urge Iran and all states to abide fully by these resolutions," the foreign ministers of France, Britain and Germany said in a joint statement after the deadline passed.