Politicians from both parties on Friday backed President Donald Trump's cruise missile strikes on Syria, while urging him to spell out a broader strategy for dealing with the conflict.

"I am hopeful these strikes will convince the Assad regime that such actions should never be repeated," said Senator Mark Warner, Virginia Democrat.

But Warner, who said he had been briefed on the strikes by Director of National Intelligence Dan Coats, urged Trump, a Republican, to lay out his plans for the multi-sided Syria conflict.

"President Trump has said repeatedly that his objective in Syria is to defeat (Islamic State militants). Last night's strike was aimed at a different objective," he said in a statement.

"President Trump needs to articulate a coherent strategy for dealing with this complex conflict, because the consequences of a misstep are grave."

Armed Services Committee chairman, Senator John McCain, who has long called for more aggressive action against Assad, said "the signal I think that was sent last night ... was a very, very important one."

Trump, he said, should be "prepared to take other action," including establishing safe zones within Syria and further arming and training of anti-Assad rebels.

Several lawmakers said Trump should seek Congress' approval if he decides to take additional military action in Syria. - Reuters