U.S. President Barack Obama said Wednesday it is the international community's credibility that is at stake if Syria's alleged chemical attacks on its people are not addressed.
Speaking at a news conference in Stockholm with Swedish Prime Minister Fredrik Reinfeldt, Obama says he did not set a "red line" regarding a use of chemical weapons, but that the line was set when world powers approved a treaty against the use of chemical weapons.
Obama said he and the Swedish prime minister were in agreement that the international community could not be silent in the face of "barbarism" in Syria and that a failure to act would increase the possibility of further attacks.
"I do think we have to act because if we do not, we are effectively saying that even though we may condemn it and issue resolutions and so forth and so on, somebody who is not shamed by resolutions can continue to act with impunity. And, those international norms begin to erode and other despots and authoritarian regimes can start looking and saying 'that's something we can get away with."
Obama is on a one-day visit to Stockholm before flying to Russia for the G20 summit in St. Petersburg, where Syria is expected to be high on the agenda.
Russian President Vladimir Putin has made comments on Syria that could raise tensions before he hosts Mr. Obama and other G20 leaders.
Putin, on Wednesday, said U.S. Secretary of State John Kerry was "lying" when he said the Syrian opposition had become more infiltrated by al-Qaida.
The Russian president also said the U.S. Congress would be sanctioning "aggression" if it approved a U.S. force against Syria, without the support of the U.N. Security Council.
Earlier Wednesday, Putin said he had not ruled out supporting a U.N. authorization of military force against Syria if there is proof government forces used chemical weapons against civilians.
He told the Associated Press and Russian television that the United States should present "convincing" evidence to the U.N.
In another development, a key U.S. Senate committee could vote as early as Wednesday on a measure authorizing U.S. military force. Leaders of the Foreign Relations Committee agreed late Tuesday on details of the plan that would give Obama authority to order limited strikes against Syrian military targets.
The resolution must clear the committee and gain approval in the full Senate and House of Representatives before taking effect.
France also says it has evidence Syrian forces were responsible for the deadly attack near Damascus last month. The country's parliament is debating a possible military response in a session Wednesday, though French President Francois Hollande does not need lawmakers' approval to act.
Syria has denied using chemical weapons, alleging it was the rebels who deployed them.