Officials initially resisted such a move, citing escalation concerns and uncertainty over how Putin would respond. Some of those officials, including in the White House, the Pentagon and the State Department, feared lethal retaliation on U.S. military and diplomatic personnel and attacks on NATO allies.

The Pentagon confirmed Russia’s missile was a new, experimental type of intermediate-range missile based on its RS-26 intercontinental ballistic missile.

Russian President Vladimir Putin said his forces may use a new missile again after targeting Ukraine in retaliation for Kyiv’s use of American and British-made weapons on Russian territory this week.