US 'prepared to do more' in Syria if chemical weapons used again The stern comments came from U.S. ambassador to the U.N. Nikki Haley.

 -- After launching air strikes against a Syrian air base on Thursday, the U.S. indicated that while it had no plans for any further escalation against the government of Syrian President Bashar al-Assad, it could not be totally ruled out either.

"We are prepared to do more, but we hope that will not be necessary," Nikki Haley, the U.S. ambassador to the U.N., said during an emergency U.N. Security Council meeting on Friday. "The United States will not stand by when chemical weapons are used. It is in our vital national security interest to prevent the spread and use of chemical weapons."

U.S. lawmakers, even those who supported the U.S. strikes, were unsure what the Trump administration might do next to follow up its policy.

“We don’t have the benefit of a larger strategy, for the same reason that I think the previous administration had difficulty coming up with a strategy, because it’s very, very complicated,” Sen. John Cornyn, the second-highest ranking Republican in the Senate, said Friday after a meeting with the Chair of Joint Chiefs of Staff.

"It was fuzzy in terms of where do we go from here," added Rep. Eliot Engel, D-N.Y., the top Democrat on the House Foreign Affairs Committee. "Essentially, the vice president's going to be contacting Congress within the next few days, give us an indication of where their heads are at [in the White House]."

Assad's office said in a statement Friday that the U.S. "naively followed a false and lying propaganda campaign" that led it to "carry out this irresponsible recklessness."

While the Syrian air base targeted by the U.S. strike incurred heavy damage, two Syrian jets were nonetheless able to take off Friday from the location to carry out strikes on areas under ISIS control in the countryside of eastern Homs, according to the Syrian Observatory for Human Rights.

The Syrian government responded to Thursday night's U.S. strike on its Shaayrat air base by quickly fixing the base and allowing the two planes to take off from there, the human rights organization said.

A U.S. official said Syrian planes took off from the base Friday but did not confirm the actions subsequently taken.

Meanwhile, Haley and other Trump administration officials like Secretary of State Rex Tillerson have blasted Russia for its military support of the Syrian government, and called on Moscow to change its calculus after the U.S. strikes.

Tillerson is slated to travel to Moscow next week for meetings with Russian officials.

"The world is waiting for the Russian government to act responsibly in Syria," Haley said Friday. "The world is waiting for Russia to reconsider its misplaced alliance with Bashar Assad."

Yet there was little evidence that any change was coming.

Speaking at the same U.N. Security Council session, Russia's deputy U.N. envoy offered a scathing rejoinder to the U.S. actions.

"We strongly condemn the illegitimate actions by the U.S.," said Vladimir Safronkov. "The consequences of this for regional and international stability could be extremely serious."

According to The Associated Press, Iranian President Hassan Rouhani on Saturday called for an international fact-finding mission to determine the causes of the Tuesday's chemical attack that killed 87 Syrian civilians, which was the stated reason for the U.S. decision to strike the Syrian air base on Thursday.

Iran and Russia have been the Assad government's primary national backers during the six-year old Syrian civil war.

Meanwhile, many U.S. allies registered support for Thursday's military action.

The Saudi Press Agency on Saturday said that Saudi King Salman called President Trump on Friday to express his support for the U.S. attack, which he called a "courageous decision."

Turkey indicated on Saturday it hoped the Trump administration would do more.

Turkey's Foreign Minister Mevlut Cavusoglu called the attack a "cosmetic intervention" unless Assad is forced from power.

ABC News' Mary Bruce and The Associated Press contributed to this report.