The administration of United States President Barack Obama says it is prepared to rework the language in a draft resolution authorising military force in Syria to address concerns from congressional leaders.
The White House says it is open to changes within the parameters Mr Obama has previously explained.
The comments follow a meeting between Mr Obama and one of the leading opposition senators, John McCain.
As he was leaving the White House, Mr McCain said a vote by Congress against Mr Obama's proposal for using military force in Syria would be catastrophic and would undermine the credibility of the United States and the US presidency, Reuters reports.
Congress will not vote on Mr Obama's request to authorise the use of force until after it officially returns from recess next week.
Mr Obama made the formal request on Sunday in response to the chemical attack the US says Syrian Government forces launched against civilians in Damascus last month.
Meanwhile, France has released its own intelligence report which concludes the Syrian Government launched the attack.
The report says technical analysis of rockets at the scene shows they were adapted for chemical weapons.
It also says the Syrian Government bombed the area after the attack, to destroy evidence and delay the arrival of United Nations inspectors.
NATO secretary-general Anders Fogh Rasmussen says a firm international response is needed to the attack.
He said he is convinced Syrian President Basher al-Assad's forces were responsible for what he called a despicable act.
"We believe that these unspeakable actions which claimed the lives of hundreds of men, women and children cannot be ignored," he says.
Mr Rasmussen says chemical weapons are horrific and barbaric arms that have no place in the 21st century.