Western governments ratcheted up the pressure for UN Security Council action against Syria on Wednesday with France branding blocking moves by China and Russia "indecent."
US President Barack Obama said Syrian leader Bashar al-Assad had no legitimacy after repeatedly ducking opportunities for reform, as ties between Damascus and Western governments nosedived after pro-regime protesters attacked the US and French embassies.
An explosion meanwhile hit a pipeline in northeastern Syria in the first attack on the country's energy infrastructure since unprecedented protests against Assad's rule erupted in March, state media and activists said.
France, which with other European governments has been circulating a draft resolution at the UN Security Council for months only to see it blocked by veto-wielding permanent members China and Russia, said it was vital the world body take action over Assad's deadly crackdown on dissent.
"It is indecent because Bashar Al-Assad has mobilised incredible resources to neutralise his opposition," said Defence Minister Gerard Longuet.
"Countries... like China... and Russia must accept common rules -- one does not deal with one's opposition with cannon fire," he told the LCI news channel.
Human rights groups say Syrian security forces have killed at least 1,300 civilians and arrested more than 12,000 in a crackdown in which security service agents backed by troops have gone house-to-house to crush any display of dissent.
French Prime Minister Francois Fillon said on Monday that it was "no longer acceptable" that Russia and China were allowed to block the draft resolution on Syria.
Obama told CBS television that Assad had "missed opportunity after opportunity to present a genuine reform agenda.
"More broadly, I think that increasingly you're seeing President Assad lose legitimacy in the eyes of his people," Obama said.
Washington had made it clear "that what we've seen on the part of the Syrian regime has been an unacceptable degree of brutality directed at its people," the US president said.
Mobs attacked the US and French embassies on Monday after the ambassadors of the two Western countries last week travelled to the flashpoint protest city of Hama, north of the capital.
Obama scolded Assad's government over the attack, saying Washington had "sent a clear message that nobody can be messing with our embassy and that we will take whatever actions necessary in order to protect our embassy."
Assistant Secretary of State for Human Rights Michael Posner told US lawmakers at a hearing on Capitol Hill that there could be further sanctions than those signed by Obama in an executive order in May.
Those sanctions allow Washington to freeze any assets owned in the United States by Assad and his top aides and ban any individuals or US companies from dealing with them.
"We've done quite a bit already and we're exploring other sanctions," Posner said, adding the situation in Syria "remains grim," with "numerous reports of attacks on civilians, including children."
Germany said Tuesday it would back a push for the UN Security Council finally to adopt the draft resolution condemning Syria.
"What has happened in the last days and hours shows us that the common language of the international community is necessary, is decisive, is crucial," German Foreign Minister Guido Westerwelle told journalists in New York.
In Syria's main oil- and gas-producing region in Deir Ezzor province in the northeast, an explosion hit a gas pipeline near the town of Mayadin late on Tuesday, the director of the London-based Syrian Observatory for Human Rights, Rami Abdel Rahman, told AFP in Nicosia.
State-owned Al-Ikhbariya television said it was an oil pipeline that was hit and that the blast had caused no casualties and only "limited damage".