After U.K. Prime Minister Theresa May said her government had concluded it is "highly likely" that the Kremlin was behind the nerve agent attack on ex-Russia spy Sergei Skripal and his daughter, President Trump said he'll condemn Russia if he agrees with the U.K.'s findings after reviewing them.

The backdrop: Rex Tillerson got out ahead of the White House, saying last night that Russia was "clearly" responsible, after Press Secretary Sarah Sanders declined to point the finger. Now Tillerson is out, and Trump is backing off that position, though he did suggest that he'd be inclined to believe the U.K. assessment.

Why it matters: Theresa May gave Russia until Wednesday to provide an explanation as to how a weapon it produced came to be used in an attempted murder on U.K. soil, and warned there would be serious repercussions if no explanation was forthcoming. She will be counting on U.S. support on this issue.

The latest: Russian foreign minister Sergey Lavrov said Moscow "is not to blame." Trump is scheduled to speak with May today.