Sen. Marco Rubio on Friday expressed concern about the possibility that Syria could respond to U.S. airstrikes launched against its regime by launching a chemical attack against Americans.

“Syrians don’t have the capacity to retaliate against the United States other than, perhaps, doing asymmetrical things -- or a chemical attack,” the Florida Republican said in an interview with “CBS This Morning.”

Rubio pointed out that there are hundreds of U.S. troops serving as military advisers in Syria.

“If Assad is willing to use sarin gas against his own people -- civilians -- he’s probably willing to use [it] against Americans,” he said.

The missile strikes launched Thursday night targeted an airfield from which the aircraft believed to have launched the chemical attack earlier this week is believed to have taken off. Rubio said he hopes the White House now realizes that as long as Syrian President Bashar al-Assad remains in power, the other radical elements in the country like al-Nusrah and the Islamic State in Iraq and Syria (ISIS) will also remain.

Rubio, who opposed President Obama’s proposed military strike on Syria in 2013, said Assad must be removed by a combination of things on the ground, but not by “foreign fighters” or “foreign forces.”

“Ultimately, I think you’ve got to have Sunni -- which is the majority in Syria -- a Sunni, non-jihadist alternative, which is what we should have done back in 2011 and I hope now the work will begin to carve out a space for them to be able to grow and get more powerful,” he said.

He reiterated his suggestion that Secretary of State Rex Tillerson’s comments last week in which he appeared to abandon the policy of regime change in Syria, gave Assad “license” to attack his own people.

“I do believe that when the sentiment is out there that somehow we have given up on efforts to remove him and that in fact he’s going to stay, I do think it gave him license or perhaps an incentive to believe he could get away with something like this,” he said.