(Adds Bonino, Cameron, Osborne, Pushkov)
* Hollande says France still ready for punitive action
* Britain will take no part after parliament votes no
* UN team to leave Syria on Saturday after investigation
* Italy urges no action without U.N. approval
By Catherine Bremer
PARIS, Aug 30 (Reuters) - France said on Friday it still backed action to punish Syrian President Bashar al-Assad's government for an apparent poison gas attack on civilians, despite a British parliamentary vote against a military strike.
An aide to Russian President Vladimir Putin, a close Assad ally, seized on Thursday's British "no" vote which set back U.S.-led efforts to intervene against Assad, saying it reflected wider European worries about the dangers of a military response.
U.S. Defense Secretary Chuck Hagel said his country would keep seeking an international coalition to act together on Syria, where hundreds of people were killed in last week's reported chemical attacks. Syria denies using chemical weapons.
"It is the goal of President (Barack) Obama and our government ... whatever decision is taken, that it be an international collaboration and effort," he said.
Any military strike looks unlikely to happen at least until U.N. investigators report back after leaving Syria on Saturday.
French President Francois Hollande told the daily Le Monde he still supported taking "firm" punitive action over an attack he said had caused "irreparable" harm to the Syrian people, adding that he would work closely with France's allies.
Britain has traditionally been the United States' most reliable military ally. However, the defeat of a the government motion authorising a military response in principle underscored misgivings dating from how the country decided to join the U.S.-led invasion of Iraq in 2003.
Russia, Assad's most powerful diplomatic ally, opposes any military intervention in Syria, saying an attack would increase tension and undermine the chances of ending the civil war.
Putin's senior foreign policy adviser Yuri Ushakov said the British vote represented majority opinion in Europe.
"People are beginning to understand how dangerous such scenarios are," he told reporters. "Russia is actively working to avert a military scenario in Syria."
Russia holds veto power as a permanent U.N. Security Council member and has blocked three resolutions meant to press Assad to stop the violence since a revolt against him began in 2011.
U.S. officials suggested that Obama would be willing to order limited military action even without allied support.
"He (Obama) believes that there are core interests at stake for the United States and that countries who violate international norms regarding chemical weapons need to be held accountable," the White House said after the British vote.
British Prime Minister David Cameron said he regretted parliament's failure to back military action in Syria but he hoped Obama would understand the need to listen to the wishes of the people. "I don't think it's a question of having to apologise," he said in a television interview.
Finance minister George Osborne, one of Cameron's closest allies, accepted that the vote had raised questions about Britain's future relations with its allies.
"There will be a national soul-searching about our role in the world and whether Britain wants to play a big part in upholding the international system," he said.
Pro-Kremlin lawmaker Alexei Pushkov said the British vote had damaged the case for military action. "Britain's refusal to support aggression against Syria is a very strong blow to the position of the supporters of war, both in NATO and in the United States. The rift is growing deeper," he said on Twitter.
Hollande is not constrained by the need for parliamentary approval of any move to intervene in Syria and could act, if he chose, before lawmakers debate the issue on Wednesday.
"All the options are on the table. France wants action that
is in proportion and firm against the Damascus regime," he said.
"There are few countries that have the capacity to inflict a sanction by the appropriate means. France is one of them. We are ready. We will decide our position in close liaison with our allies," Hollande said.
In a briefing with senior lawmakers on Thursday, Obama administration officials said they had "no doubt" Assad's government had used chemical weapons, U.S. Representative Eliot Engel, who joined the call, told Reuters.
U.S. officials acknowledged they lacked proof that Assad personally ordered last week's poison gas attack, but in a call with lawmakers, cited "intercepted communications from high-level Syrian officials" among other evidence, Engel said.
Some allies have warned that military action without U.N. Security Council authorisation may make matters worse.
Italian Foreign Minister Emma Bonino said on Friday there should be no attack without a U.N. resolution, expressing concern about how Assad's allies, including the Shi'ite militia Hezbollah in neighbouring Lebanon, would respond.
"There's talk of targeted attacks, but it's clear that all attacks begin as targeted attacks. Syria will react and we must fear how Hezbollah, Russia and Iran could react. An already dramatic and terrible conflict risks turning into a global conflagration," she said in an interview broadcast on SkyTG24.
"Even if it seems slower, more difficult and sometimes does not seem to be working, keeping the diplomatic and political pressure high is the only possible solution."
Expectations of imminent turmoil eased as the diplomatic process was seen playing out into next week, and the White House emphasised that any action would be "very discrete and limited", and in no way comparable with the Iraq war.
Syrian opposition sources said on Thursday Assad's forces had removed Scud missiles and launchers from a base north of Damascus, possibly to protect them from a Western attack, and Russia was reported to be moving ships to the region.
Damascus says rebels perpetrated the gas attacks, which occurred when U.N. chemical weapons inspectors were already in Syria. Washington and its allies dismiss this version.
The U.N. investigators visited a military hospital in a government-held area of Damascus on Friday to see soldiers affected by an apparent chemical attack, a Reuters witness said.
The inspectors have spent the week visiting rebel-controlled areas on the outskirts of Damascus affected by gas attacks.
Witnesses said the investigators were meeting soldiers at the Mezze Military Airport who state media said were exposed to poison gas after finding chemical agents in a tunnel used by rebels in the Damascus suburb of Jobar last Saturday.
CHINA OPPOSES HASTY U.N. ACTION
The United Nations says the team will leave Syria on Saturday and report to Secretary-General Ban Ki-moon.
The United States, Britain and France have said action could be taken with or without a U.N. Security Council resolution, which would probably be vetoed by Russia and perhaps China.
Western diplomats say they are seeking a vote in the 15-member Council on a draft measure, which would authorise "all necessary force" in response to the alleged gas attack, to isolate Moscow and show that other nations back military action.
But China said there should be no rush to force a council decision on Syria until the U.N. inspectors complete their work.
"Before the investigation finds out what really happened, all parties should avoid prejudging the results, and certainly ought not to forcefully push for the Security Council to take action," Foreign Minister Wang Yi told U.N. Secretary-General Ban Ki-moon in a phone call, Xinhua reported.
Hollande told Le Monde it was now an "established fact" that chemical weapons had been used in Damascus and said France had "a stack of evidence" that Assad's forces were responsible.
China's foreign minister told his French counterpart Laurent Fabius by telephone that it was important to determine not only if chemical weapons were used but who used them.
The samples collected by U.N. inspectors in Syria will be analysed in Sweden and Finland, a Swedish paper reported, quoting a United Nations spokesman.
Elaborate bio-metric analysis of blood, hair or urine samples is expected to be done in laboratories, which are among 22 used by the Organisation for the Prohibition of Chemical Weapons (OPCW) in 17 countries.
"The labs are OPCW-bonded labs in Sweden and Finland, with back-ups in Germany and Switzerland. They are pre-assigned as per OPCW standards," the spokesman, Farhad Haq, said in an email sent late on Thursday, Swedish technology weekly Ny Teknik said. (Additional reporting by Matt Spetalnick, Andrea Shalal-Esa, Patricia Zengerle, Steve Holland, Thomas Ferraro and Jeff Mason in Washington, Erika Solomon and Oliver Holmes in Beirut, Khaled Yacoub Oweis in Amman, Sarah Marsh in Berlin, Timothy Heritage in Moscow, Phil Stewart in Manila, Louis Charbonneau and Michelle Nichols at the United Nations, Lidia Kelly in Moscow, Ben Blanchard and Michael Martina in Beijing, John Irish in Paris and Andrew Osborn, Marie-Louise Gumuchian and Peter Apps in London; Writing by Alistair Lyon; editing by David Stamp)