PARIS (Reuters) - President Francois Hollande said on Tuesday that France stood ready to punish those behind a chemical attack on civilians in Damascus last week and would increase its military support to the Syrian opposition.
Hollande said it seemed certain that forces loyal to President Bashar al-Assad were behind the chemical attack - believed to have killed hundreds of civilians - and said it was the outside world's responsibility to respond.
He said he recognized a 2005 U.N. doctrine on the responsibility to protect civilians, something a Western-led coalition might use to legitimize any retaliatory strike if unable to obtain a broad Security Council resolution.
"France is ready to punish those who took the decision to gas the innocent," Hollande told an annual meeting in Paris of dozens of French ambassadors posted around the world.
"I recognize the right to protect civilian populations that the U.N. General Assembly voted in 2005," he added.
U.S. and European officials say that a short, sharp attack, perhaps entirely with cruise missiles, could be the preferred response by a Western-led coalition to last week's attack.
French business magazine Challenges reported in its online edition on Tuesday that France's Charles de Gaulle aircraft carrier was being sent to the eastern Mediterranean from its current berth in the southern French port of Toulon.
The Defence Ministry, Foreign Ministry and spokespeople for the armed forces and navy all denied the report.
A French diplomatic source told reporters earlier on Tuesday that the attack had defied international law and France "would not shirk its responsibilities" in responding.
The source said Hollande, one of Assad's firmest critics since the start of the two-year conflict, believed that Russian opposition to a U.N. Security Council Resolution on Syria would force others to act outside its mandate.
Asked if military action was now inevitable, he said: "It sounds logical." He added that any strikes could happen very quickly and they would be more of a punitive operation than an attempt to bring down Assad's government.
"A moral taboo has been crossed with the use of chemical weapons and we can't accept this," he said. "It is possible to get strong support for a mission to punish and dissuade, but it would be complicated to go further," he added.
The United Nations agreed its doctrine on the responsibility to protect civilians - used during the conflict in Libya - at a plenary meeting of the General Assembly in 2005. Any operation under the doctrine should still have Security Council backing.
The diplomatic source said the continued defense of Assad by Moscow, which holds a Security Council veto, meant that if there were a retaliatory operation it would not happen under Chapter 7 of the U.N. charter, which allows the Council to authorize actions ranging from sanctions to military intervention.
(Reporting by John Irish and Julien Ponthus; Writing by Catherine Bremer; Editing by Alison Williams)