President Donald Trump on Tuesday fired FBI chief James Comey, who was leading a wide-ranging probe into whether Trump aides colluded with Russian officials to sway last year's election, which saw the Republican billionaire defeat Democrat Hillary Clinton.

"I want to welcome the foreign minister to the State Department and express my appreciation for him making the trip to Washington so that we could continue our dialogue and our exchanges that began in Moscow," Tillerson told reporters.

After talks with Tillerson, Lavrov will head to the White House to meet Trump -- an unusual Oval Office welcome for a foreign minister.

Lavrov cracked a joke about Comey's firing, answering shouted questions from reporters by saying: "Was he fired?... You're kidding, you're kidding!"