Russian President Vladimir Putin on Tuesday signed a measure to formally suspend the last remaining nuclear arms pact with the United States amid high tensions over the war in Ukraine.

Russia will no longer take part in the New START treaty, according to the bill he signed that was published by the Kremlin. The document says that it’s up to the president to decide whether Moscow could return to the pact.

Putin had declared a week ago in his state-of-the-nation address that Moscow was suspending its participation in the 2010 New START treaty. He had charged that Russia can’t accept U.S. inspections of its nuclear sites under the pact at a time when Washington and its NATO allies have openly declared Russia’s defeat in Ukraine as their goal.

Both houses of parliament quickly ratified Putin’s bill on the pact’s suspension last week. On Tuesday, Putin signed it into law, effective immediately.