PARIS - The United States and France claimed growing international support for military strikes to punish the Syrian regime for an alleged chemical attack, after EU nations called for a "strong response".
Both Washington and Paris said Saturday that more countries were getting behind the need for military action after European Union nations condemned "the cynical use of chemical weapons".
US Secretary of State John Kerry said the number of countries ready to take military action was now in the "double digits", after holding talks in Lithuania with EU foreign ministers.
Following the meeting, the EU ministers issued a call for action against Syrian President Bashar al-Assad's regime.
The EU did not explicitly back military action, but Kerry said he was "encouraged" by the "very powerful statement" made by the bloc. There were "a number of countries, in the double digits, who are prepared to take military action," he said.
"We have more countries prepared to take military action than we actually could use in the kind of military action being contemplated." The US accuses the Assad regime of gassing more than 1,400 people to death in an August 21 attack outside Damascus.
In his weekly address, President Barack Obama warned of the dangers of turning "a blind eye" to chemical attacks.
"I call on members of Congress, from both parties, to come together and stand up for the kind of world we want to live in," Obama said. The president has just returned from a G20 summit in Saint Petersburg that deadlocked over the Syria crisis.
Obama has asked for Congress to authorise strikes on Syria. The legislature reconvenes Monday and the president is set to address the nation Tuesday about the US response.
Kerry said Obama had made no decision about whether to wait for the release of a UN investigation into the August attack before taking action. French President Francois Hollande, who has said Paris will wait for the results of the UN probe, said he expected the report to be ready by next weekend.
Hollande said he also expected a US Congress vote on "Thursday and Friday".
Facing a 'Munich moment'
Outlining his case in Paris in French and English, Kerry compared the situation to the 1938 Munich Agreement, which ceded control of part of Czechoslovakia to Nazi Germany.
"This is our Munich moment, this is our chance to join together and pursue accountability over appeasement...," said Kerry at a joint news conference with French counterpart Laurent Fabius.
"This is not the time to be silent spectators to slaughter." Fabius told reporters there was "wide and growing support" for action on Syria.
"Right now, seven of the eight countries in the G8 share our opinion on a strong reaction and 12 countries of the G20 also share this opinion," he said. Split between Britain and France, who back US-led military action, and nations reluctant to act without a United Nations mandate, the EU ministers managed to hammer out a compromise in Lithuania.
A statement read out by EU foreign policy chief Catherine Ashton dubbed the suspected chemical attack "a war crime and a crime against humanity". There was "strong evidence that the Syrian regime is responsible," the statement said.
"In the face of this cynical use of chemical weapons, the international community cannot remain idle. "A clear and strong response is critical to make clear that such crimes are unacceptable and that there can be no impunity."
The statement called on the UN Security Council "to fulfil its responsibilities", a reference to Russia and China's repeated refusals to punish Assad.
In Riyadh, the Gulf Cooperation Council urged the international community to intervene immediately to "rescue" the Syrian people from "oppression". Pope Francis meanwhile led Catholics worldwide in a day of fasting and prayer for peace in Syria joined by Jews, Muslims and Orthodox Christians. Addressing thousands of people massed for a vigil in St Peter's Square, he called for reconciliation and peace.
Faced with a war-weary US public and little international support, Obama is bracing for an uphill battle to convince American lawmakers to back military action against Assad's regime.
According to a Washington Post survey, 224 of the current 433 House members were either "no" or "leaning no" on military action as of Friday. A large number, 184, were undecided, with just 25 backing a strike. US broadcaster CNN aired graphic videos Saturday it said were shown to members of the US Senate Intelligence Committee in a bid to win support for a strike on Syria.
The senators were told the images depicted victims of the August 21 attack. Excerpts depicted convulsing children and men sprawled on the floor apparently vomiting and foaming at the mouth.
In France, the sole EU nation determined to join a US-led strike, the latest public opinion poll showed 68 per cent of people opposed to military action, nine percentage points up since late August.
On Sunday, Kerry will meet Arab League officials in Paris to update them on Syria - and on progress in the Israeli-Palestinian peace process - before flying to London for talks with Palestinian president Mahmud Abbas.