U.S. faults Russia on arms control, will watch carefully

U.S. Secretary of State Antony Blinken visits Greece

By Humeyra Pamuk and Arshad Mohammed

(Reuters) -The United States on Tuesday called Russia's decision to suspend participation in their last major pillar of nuclear arms control irresponsible but it also left room for Moscow to reverse course.

President Vladimir Putin delivered a nuclear warning to the West over Ukraine, suspending the New START bilateral arms control treaty, announcing new strategic systems had been put on combat duty and warning that Moscow could resume nuclear tests.

He spoke a day after U.S. President Joe Biden visited Kyiv to show U.S. support for Ukraine in its war with Russia, which began with Russia's Feb. 24 invasion and has killed tens of thousands of civilians and soldiers on both sides.

"The announcement by Russia that it's suspending participation is deeply unfortunate and irresponsible," U.S. Secretary of State Antony Blinken told reporters in Athens.

"We'll be watching carefully to see what Russia actually does. We’ll of course make sure that in any event, we are postured appropriately for the security of our own country and that of our allies."

The U.S. response reflects a studied calm in response to Putin's statements, a U.S. official and two U.S. analysts said, saying it was not entirely clear what the statements might mean and Washington wanted to leave room for Moscow to change course.

"In this charged atmosphere, I think it's entirely sensible to sound cool, calm and collected," said Eugene Rumer, a former U.S. national intelligence officer for Russia and Eurasia now at the Carnegie Endowment for International Peace think tank.

"By suspension as opposed to withdrawal, it appears as though Russia intends to stay within the central limits of the treaty," said Daryl Kimball of the Washington-based Arms Control Association.

The Russian foreign ministry later said Russia will continue to observe limits on the number of nuclear warheads it can deploy under the treaty despite Putin's announcement.

Signed in 2010 and due to expire in 2026, the treaty caps the number of strategic nuclear warheads that the countries can deploy. Under its terms, Moscow and Washington may deploy no more than 1,550 strategic nuclear warheads and 700 land- and submarine-based missiles and bombers to deliver them.

The United States is still trying to understand what Putin may have meant, a U.S. official said.

"We don’t have any better sense of what exactly this means. It may have just been a talking point, or it may have signaled an intention to back away from the treaty in more substantive ways," said a U.S. official who spoke on condition of anonymity.

Blinken left the door open to resuming arms control talks with Russia at any time. Two of the treaty's key elements - on-site inspections and meetings of the bilateral commission to implement the pact - are already in abeyance. It remains unclear if Russia will continue to exchange data under the treaty.

While both sides agreed in early 2021 to extend the treaty for five years, tensions over the pact have been mounting for some time and Washington on Jan. 31 accused Moscow of violating it by refusing to allow inspection activities on its territory.

"We remain ready to talk about strategic arms limitations at any time with Russia, irrespective of anything else going on, in the world or in our relationship," he said

(Reporting by Humeyra Pamuk in Istanbul and Arshad Mohammed in Saint Paul, Minn.; Writing by Doina Chiacu and Arshad Mohammed; Editing by Andrew Heavens and Alistair Bell)