French President Francois Hollande expressed willingness today to push ahead with plans to strike Syria for allegedly using chemical weapons despite the British parliament's rejection of military action.
Washington also was preparing for the possibility of a strike against the Damascus regime within days.
But the German government says it has no plans to join military action against Syria. Government spokesman Steffen Seibert told reporters in Berlin today that "we haven't considered any German military participation and still aren't doing so"
Mr Hollande told the Le Monde newspaper that "the chemical massacre of Damascus cannot and must not remain unpunished". He spoke as UN experts in Damascus began what is expected to be the last day of their probe into the alleged attack.
The French president reiterated that France wants a "proportional and firm action." When asked about the type of intervention, however, he said "all options are on the table."
Mr Hollande suggested that action could even come ahead of Wednesday's extraordinary session of the French Parliament, called to discuss the Syria situation; MPs' approval is not needed for Mr Hollande to order military action.
"I will not take a decision before having all the elements that would justify it," he told Le Monde. However, noting that he had convened parliament, he added: "And if I have (already) committed France, the government will inform (lawmakers) of the means and objectives."
The British parliament voted late Thursday against military action in Syria, whittling down the core of the planned coalition to the United States and France. Italy and Germany have said they won't take part in any military action.
The British 'no' vote raised questions about France's participation - and ratcheted up pressure on US President Barack Obama, who is also facing domestic scepticism about military intervention in Syria.
Amid the resistance, the US administration shared intelligence with politicians aimed at convincing them the Syrian government used chemical weapons against its people and must be punished.
Mr Obama appeared undeterred by the difficulties forming an international coalition, and advisers said he would be willing to retaliate against Syria on his own.
"The president of the United States is elected with the duty to protect the national security interests in the United States of America," said White House spokesman Josh Earnest.
France has more intimate ties to Syria, having once ruled the country; it also has warplanes and strategic interest in the region. Paris has embraced the Syrian opposition and urged a firm response against Assad over the purported August 21 chemical weapons attack outside Damascus. But Mr Hollande appears to be facing increasing political and public resistance against moving against Syria quickly.
He said that France is among the few nations capable of "inflicting a sanction by the appropriate means" and "it is ready." But a decision will be made in close coordination with allies, he added.
French military analysts say France's most likely role would be from the air, including use of Scalp cruise missiles that have a range of about 500 kilometres (300 miles), fired from Mirage and Rafale fighter jets.
French fighters could likely fly directly from mainland France - much as they did at the start of a military campaign against Islamic radicals in Mali earlier this year - with support from refuelling aircraft. France also has six Rafale jets at Al Dhafra air base, near Abu Dhabi in the United Arab Emirates on the Persian Gulf, and seven Mirage-2000 jets at an air base in Djibouti, on the Red Sea.
Mr Hollande reiterated that any action is aimed at punishing the regime of Bashar Assad, not toppling him.
"I won't talk of war but of a sanction for a monstrous violation of the human person. It will have a dissuasive value," he said.
Russian Foreign Minister Sergey Lavrov has warned that military strikes would lead to long-term destabilisation of Syria and the region. He has spoken against any use of force without UN Security Council approval, which he said would be a "crude violation of international law." Russia has remained a strong ally of Syria throughout the civil war, which has left more than 100,000 people dead.
In Damascus, three UN vehicles headed out for more on-site visits today, after an early morning delay.
The UN has said that the inspectors would wrap up their investigation today and leave Syria the following day. Some of the experts will travel to laboratories in Europe to deliver the material they've collected this week during trips to the Damascus suburbs purportedly hit by toxic gas.
The mandate of the UN team is to determine whether chemical agents were used in the attack - not who was responsible. But the UN has suggested that evidence collected by investigators - including biological samples and interviews - might give an indication of who was behind the attack.
Mr Hollande said that a chemical attack is "an established fact ... and the question is to know who are the authors of this frightening act." But he reiterated what France has said for several days, that Paris has a "range of indices which point to the responsibility of the regime."
US defence secretary Chuck Hagel, issued an impassioned defence of the principles behind the planned strike.
"I don't know of any responsible government around the world ... that has not spoken out in violent opposition to the use of chemical weapons on innocent people," said Mr Hagel, adding that such attacks violate basic standards of decency.
He said that Washington would continue to seek partners in its Syria mission: "Our approach is to continue to find an international coalition that will act together."
Meanwhile, in Damascus, shops and supermarkets filled with Syrians stocking up on bread, canned food and other necessities ahead of the expected US strikes, although there appeared to be no signs of panic or food shortages. Prices have shot up because of the high demand, residents complained.
Kheireddine Nahleh, a 53-year-old government employee, said he was not particularly worried about the US threats. "We got used to the sound of shelling ... Death is the same be it with a mortar or with an American missile," he said. "I'm not afraid."
Russia, which as a firm backer of the Assad regime is fiercely hostile to military intervention, expressed bewilderment at why the UN team of inspectors was leaving Syria so soon.
"We don't quite understand why the entire team had to be going back to the Hague when there are many questions about a possible use of chemical weapons in other areas in Syria," said Yuri Ushakov, President Vladimir Putin's foreign policy adviser.