Russian President Vladimir Putin suspended Moscow's participation in the last remaining nuclear arms control pact with the United States, announcing the move Tuesday in a bitter speech in which he made clear he would not change his strategy in the war in Ukraine.

Putin emphasized, however, that Russia isn't withdrawing from the pact yet, and hours after his address the Foreign Ministry said Moscow would respect the treaty's caps on nuclear weapons. It also said Russia would continue to exchange information about test launches of ballistic missiles per earlier agreements with the United States....