France backed away Friday from joining the U.S. in swift military action against Syria, isolating President Obama even more as he threatens limited strikes on the Damascus regime for its alleged use of chemical weapons.

France had been the only nation to agree to the joint use of force with the U.S. against Syria, but French President Francois Hollande said he is now waiting for a report from United Nations weapons inspectors on whether chemical weapons were used in the Aug. 21 rocket attacks on the Damascus suburbs.

"We shall await the report of the inspectors just as we will await [the U.S.] Congress," Hollande said at a news conference in St. Petersburg, Russia, where he was attending an economic summit with Obama and other world leaders.

UN officials have said the report of the weapons inspectors may not be ready until October, and they have stressed that the findings will only show whether chemical weapons were used, and not who was responsible. Russian President Vladimir Putin has repeatedly charged that rebel forces may have been to blame, and not the regime of President Bashar al-Assad.

Before President Obama's surprise announcement last Saturday that he would seek Congressional authorization for strikes on Syria, Hollande said that the French military would support U.S. action. France has Rafale and French Mirage 2000 fighters armed with SCALP cruise missiles that could have been used as standoff weapons in an attack coordinated with U.S. air and naval assets.

At a meeting with Hollande, Obama did not directly address the French change of course. Instead, Obama thanked Hollande for his general agreement "that the chemical weapons ban is a critical international norm, and that it needs to be enforced."

At his own news conference before leaving St. Petersburg, Obama said that he would address the nation on Tuesday night on his judgment that that the U.S. must act against Syria, even if traditional allies such as Britain and France have chosen to stay on the sidelines.

"What I've been emphasizing, and will continue to stress, is that the Assad regime's brazen use of chemical weapons isn't just a Syrian tragedy, it's a threat to global peace and security," Obama said.

"Failing to respond to this breach of this international norm would send a signal to rogue nations, authoritarian regimes, and terrorist organizations that they can develop and use weapons of mass destruction and not pay a consequence," Obama said. "And that's not the world that we want to live in." Obama also gave his most detailed explanation for taking the issue to Congress, while claiming that he was not legally required to get authorization for strikes on Syria.

"I did not put this before Congress just as a political ploy or as symbolism," Obama said. "I put it before Congress because I could not honestly claim that the threat posed by Assad's use of chemical weapons on innocent civilians and women and children posed an imminent, direct threat to the United States." "In that situation, obviously, I don't worry about Congress," Obama said. "We do what we have to do to keep the American people safe."

In the case of Syria, Obama said his generals have assured him that the U.S. military "could act today, tomorrow, a month from now."