Russian President Vladimir Putin and U.S. counterpart Barack Obama on the sidelines of the G20 Leaders Summit in Hangzhou on September 5, 2016.

Russia is able to take asymmetrical and forceful measures if the United States introduces tougher sanctions on Russia, Deputy Foreign Minister Sergei Ryabkov told lawmakers on Wednesday.

Britain and the United States said on Sunday they were considering imposing additional sanctions on Syrian President Bashar al-Assad and his supporters for their actions in Syria's war.

Ryabkov was in the lower house of parliament discussing legislation related to the suspension of a treaty with Washington on cleaning up weapons-grade plutonium, something President Vladimir Putin suspended this month.

The lower house of the Russian parliament approved President Vladimir Putin's decree on suspending a plutonium accord with the United States, Russian news agencies reported.

The agreement was concluded in 2000 and bound the two sides to dispose of surplus plutonium originally intended for use in nuclear weapons.

Keep updated: Sign up to our newsletter Email * Please enter a valid email address Sign up Please wait… Thank you for signing up. We've got more newsletters we think you'll find interesting. Click here Oops. Something went wrong. Please try again later. Try again Thank you, The email address you have provided is already registered. Close

Agencies said the suspension was approved by 445 of 450 deputies in the State Duma, the lower house of parliament.

Relations at 40-year low

Russia's UN ambassador said last Friday that tensions with the United States are probably the worst since the 1973 Israeli-Arab war. But Vitaly Churkin said Cold War relations in 1973 were different than U.S.-Russia relations today.

Churkin said in an interview Friday with three reporters that "the general situation I think is pretty bad at this point, probably the worst ... since 1973."

When Egypt and Syria launched a surprise attack against Israel on Yom Kippur, the holiest day in the Jewish calendar that year, the Mideast was thrown into turmoil. And according to historians, the threat of the Soviet Union, which backed the Arabs, and the United States, Israel's closest ally, going to war at that time was the highest since the 1962 Cuban missile crisis.