A number of American senators are calling on US President Barack Obama to create a no-fly zone over Syria.

US lawmakers pressed Obama on Sunday to go beyond supplying Syrian rebels with ‘lethal aid’ and to consider imposing a no-fly zone over the Arab country.

South Carolina Republican Senator Lindsey Graham said supplying militants with automatic weapons and ammunition is not enough.

“We need to create a no-fly zone,” Graham told NBC’s “Meet the Press.” “We cannot take air power out of the equation.”

Obama has not ruled out imposing a no-fly zone in Syria.

On Thursday, Obama decided to arm insurgents in Syria based on allegded evidence that Syrian government forces had crossed a “red line” by using chemical weapons on militants.

Senator Graham was joined on the show by Georgia Republican Sen. Saxby Chambliss, who said the United States’ position must be based essentially on daily evaluations of the military situation in Syria.

“A no-fly zone may be the ultimate tactic that needs to be taken,” said Chambliss, the highest-ranking Republican on the Senate Intelligence Committee.

Colorado Democratic Sen. Mark Udall took a more measured approach, saying he is considering a range of US responses including a no-fly zone.

“I'm open to all options,” he told NBC.

The White House has recently said establishing a no-fly zone over Syria is not within the bounds of possibility as it has faced formidable obstacles not experienced in the implementation of such a measure in Libya in 2011.

Syria is grappling with unrest that erupted in March 2011, and many people, including large numbers of Syrian soldiers and security personnel, have been killed so far.