WASHINGTON (Reuters) – U.S. lawmakers 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.

In the biggest foreign policy decision of his presidency thus far, Trump ordered the firing of cruise missiles at a Syrian air base that U.S. officials said was the launching point for a deadly chemical weapons attack against Syrian civilians earlier in the week.

“I am hopeful these strikes will convince the Assad regime that such actions should never be repeated,” said Senator Mark Warner, West Virginia Democrat, referring to the government of Syrian President Bashar al-Assad.

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.”

But the Arizona Republican, speaking on MSNBC, said “despite all the enthusiasm we see this morning, if I might quote Churchill, it’s the end of the beginning not the beginning of the end.”

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.

Senator Marco Rubio, Florida Republican, said the strikes in Syria could send a message to other U.S. adversaries such as North Korea.

“I think the time has come for some of these countries to be worried about us a little bit, not us always worried about what they might do,” Rubio told Fox News.

(Reporting by David Alexander, Eric Walsh and Warren Strobel; Editing by Bernadette Baum)