Several Republican senators are criticizing the deal struck by the United States and Russia this weekend to dismantle Syria's chemical weapons cache.
The agreement calls for Syria to provide an inventory of its chemical weapons stockpile within a week.
The weapons would then come under international oversight by November before being destroyed.
But Sens. John McCain, R-Ariz., and Lindsey Graham, R-S.C., are calling the deal "an act of provocative weakness" by America.
They say it will embolden enemies like Iran.
"Is the message of this agreement that [President Bashar] Assad is now our negotiating partner and that he can go on slaughtering innocent civilians and destabilizing the Middle East using every tool of warfare so long as he does not use chemical weapons," the two senators asked in a joint statement issued separately, calling the deal "morally and strategically indefensible."
"The only way this underlying conflict can be brought to a decent end is by significantly increasing our support to moderate opposition forces in Syria," the statement read. "We must strengthen their ability to degrade Assad's military advantage, change the momentum on the battlefield, and thereby create real conditions for a negotiated end to the conflict."
On NBC's "Meet the Press," McCain called the agreement "meaningless," saying it goes soft on Syria's President Assad, despite tough talk from President Barack Obama.
"But the point is if the agreement had said that there will be the use of force automatically or the Russians had agreed that they could go under Chapter 7 to the United Nations Security Council, that puts an entirely different cast on it," McCain said. "Right now it's up to the Russians to decide that. And, by the way, they didn't even assign blame for this attack."
Meanwhile, a Lebanese newspaper reported that Syria has sent equipment that can produce chemical weapons to Iraq. That follows a similar story last week in which a Syrian opposition leader told CNN that Syria was transporting chemical weapons to Lebanon and Iraq.