WASHINGTON -- U.S. senators clashed with two top arms control officials over the fate of several major treaties with Russia, as President Donald Trump's administration has suspended compliance with one and is undecided about a second.

The May 15 hearing by the Senate Foreign Relations Committee came a day after Secretary of State Mike Pompeo held talks with Russian President Vladimir Putin and Foreign Minister Sergei Lavrov on the question of arms control, and roiling relations between Moscow and Washington, among other issues.

Senators pressed Andrea Thompson, the undersecretary of state for arms control, on whether Trump would seek to extend the New START treaty when it expires in 2021. She testified along with David Trachtenberg, one of the Defense Department's main arms control officials.

The treaty, which put a ceiling on the number of ballistic missiles, warheads, and launchers possessed by the two nations, can be extended for five years if the two sides agree.

'The administration has not made any decision on a potential extension of New START,' she said.

Robert Menendez, the ranking Senate Democrat on the committee, said he supported extending the agreement, but was visibly angry when Thompson appeared reluctant to answer if it was in the U.S. interest.

'I'm not asking Russia about our national defense. I'm asking you,' he said.

Thompson also said that the U.S. administration had not made a final decision about whether to withdraw entirely from the Intermediate-Range Nuclear Forces treaty.

In February, the administration announced it was suspending compliance with the 1987 agreement, and had begun research into ground-launched weapons that would potentially violate the treaty.

That would halt if, she said, Russia stopped its violations of the treaty. Moscow has denied those assertions.

'This research and development is designed to be reversible, should Russia return to full and verifiable compliance before August 2,' she said in prepared remarks.

Meanwhile, in the Black Sea city of Sochi, Putin told reporters that Moscow was open to talks on extending New START.

'Our fundamental New START treaty expires in 2021 and we have to decide if we want to prolong it or not. If [we want to] prolong it, it is necessary to start full-scale talks now,' he said.

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