Washington (CNN) - A top Democrat on the Senate Armed Services Committee urged the Obama administration against taking unilateral military action in Syria, in part because of how it would look in the international community.
Sen. Jack Reed said Monday on CNN's "The Situation Room with Wolf Blitzer" that unilateral action would be "a mistake" and that with a coalition the "political pressure would be sufficient" to pressure the Syrian government led by President Bashar al-Assad. Potential partners could include Great Britain, France and Turkey, he said.
"Without their participation it looks as if this is just a Western vs. Islamic struggle. It's not," he said. "This is to vindicate a basic rule of international law that these weapons will not be used, not by Iran, not by any power."
Earlier in the day, Secretary of State John Kerry said he had no doubt the al-Assad regime had used chemical weapons against their own people in an August 21 attack.
"What we saw in Syria last week should shock the conscience of the world," he said at the State Department. "It defies any code of morality. Let me be clear. The indiscriminate slaughter of civilians - the killing of women and children and innocent bystanders by chemical weapons is a moral obscenity."
House Speaker John Boehner spoke Monday afternoon with White House officials "about the situation in Syria and any potential U.S. response," Boehner spokesman Brendan Buck said.
"The speaker made clear that before any action is taken there must be meaningful consultation with members of Congress, as well as clearly defined objectives and a broader strategy to achieve stability," he said.
Sen. Tim Kaine, a Democrat from Virginia and chairman of a Foreign Relations subcommittee overseeing the region, also called for Congressional consultation.
"Absent an imminent threat to United States national security, the U.S. should not be engaged in military action without Congressional approval," Kaine said.
An unlikely international partner at this point would be Russia, which warned the U.S. against jumping to conclusions and which compared the situation to the U.S.-led invasion of Iraq a decade ago.
"The impression is…those actively calling for military intervention and bypassing the U.N., are clearly trying to scrap mutual Russian-American efforts to gather an international conference to peacefully deal with settling the crisis," Russian Foreign Minister Sergey Lavrov told Kerry on Sunday, according to the Russian government.
Reed, the senior-most Democrat on the panel behind Chairman Carl Levin or Michigan, said on CNN that the administration should continue with its diplomatic efforts because those would speak volumes to the Syrian leadership.
"I think first we have to deliver a strong international message that this behavior cannot be countenanced,” Reed said. “Second, I think we have to make it clear what our objective is, which is I think principally that these weapons will not be used and the Syrians have to put them in a situation where they won't be used.”
On Sunday, he appeared on CBS and expressed concern that the U.S. could “get into a situation where this becomes a springboard for a general military operation in Syria to try and change the dynamic."
- CNN Senior White House Correspondent Jim Acosta contributed to this report.