In an interview with CBS's Face the Nation on Sunday, McCain said, “We are seeing unfortunately a battlefield situation where Bashar Assad now has the upper hand."
McCain, who last week surreptitiously visited Syria, urged the administration of President Barack Obama to intervene immediately in the Syrian crisis, claiming that the longer the US waited the more the situation was unraveling.
He added that Assad is unlikely to step down, which is what the US and its allies want him to do.
Commenting on the expected participation of the Syrian government delegation in the upcoming Geneva peace talks, McCain said, "Anyone that believes that Bashar Assad is going to go to a conference in Geneva when he is prevailing on the battlefield, it's just ludicrous to assume that."
At a meeting in Moscow on May 7, Russia and the United States reached an agreement to convene an international conference on Syria, which would serve as a follow-up to an earlier Geneva meeting held in June 2012.
On Wednesday Syrian government announced that they are ready to enter the talks with no preconditions. However opposition groups which enjoys support from Syrian government arch foes such as United States, Qatar and Saudi Arabia, said they are not going to take part in any dialogue because Lebanon’s Hezbollah supports Assad.
On Friday, McCain said the Syrian militants are in dire need of “ammunition and heavy weapons” as the government troops are gaining ground in the crisis-hit country.
“There’s no doubt that they (the militants) need some kind of capability to reverse the battlefield situation, which right now is in favor of Assad," he said.
McCain, who is a member of the Armed Services and Foreign Relations committees, has been an outspoken supporter of arming the militants in Syria, a stance the Obama administration has shied away from adopting officially though there have been reports of the US role in coordinating the shipment of arms to the militants through Turkey and Jordan.