In his speech, McCain said any military aid should not include U.S. ground forces, but should include other military might from the United States and its allies, such as European and other Arab countries.
McCain rejected characterizations of the current state of affairs inside Syria as a civil war. "It's not a civil war because all the military strength is on one side, and not the other," he said. "At least we ought to give them a chance to have a fair fight."
The suspension of the monitoring mission is a major blow to Annan's peace plan, which had become a symbol of hope for a country torn by relentless attacks during the 15-month uprising.
The Syrian government has blamed the violence on "armed terrorist groups," the vaguely defined entities it has consistently blamed over the past year.
Syrian opposition groups say more than 13,000 people have been killed since al-Assad's government started cracking down on anti-government protesters last year. The United Nations' latest estimate puts the death toll at more than 10,000.
CNN cannot independently verify government and opposition claims of casualties because the Syrian government has restricted access by international journalists.