Paul said in an interview in his Capitol Hill office on Thursday that US "over-eagerness" for war is leading Washington into one quagmire after another.

"I think it's a big mistake" to support the Syrian militants, he said, citing some groups' loose connections with terror groups like Al-Qaeda and al-Nusra Front, and how US weapons could find their way into the hands of extremists.

"I think it shouldn't happen unless there's a vote of Congress," he added.

"We can't be the world's savior," said Paul, who has unsuccessfully urged Congress to pull the plug on US aid to Egypt, Libya and Pakistan.

On June 20, four American senators introduced legislation that would bar President Barack Obama from providing military aid to militants in Syria.

The bill would prevent the Department of Defense and US intelligence agencies from using any funds to support military, paramilitary or covert operations in Syria, directly or indirectly.

The bill's sponsors -- Democrats Tom Udall of New Mexico and Chris Murphy of Connecticut and Republicans Mike Lee of Utah and Rand Paul of Kentucky -- expressed doubts about Washington's ability to ensure weapons will not fall into the wrong hands, and called for debate in Congress before the United States becomes more involved in Syrian conflict.

"The president's unilateral decision to arm Syrian rebels is incredibly disturbing, considering what little we know about whom we are arming," Paul said in a statement.

Other lawmakers argued it was in the US national security interest to get more involved in Syria.

"This is about looking at the possibility of a failed state in which terrorist actors already present within Syria in this fight can launch attacks against our allies, and potentially against the United States," Democrat Robert Menendez of New Jersey, chairman of the Senate Foreign Relations Committee, told reporters.

After months of equivocating, Obama decided a week ago to provide military aid to terrorists trying to overthrow Syrian President Bashar al-Assad.

Syria's 27-month conflict appears to be reaching a turning point after government troops re-captured the town of Qusayr, in central Homs Province near the Lebanese border, earlier this month.

Syria’s army has since turned its attention to retake Aleppo, the Damascus suburbs and parts of the south of the country where they have been mired in a bloody stalemate with the terrorists for nearly a year.