DAMASCUS (AFP) - Syria's President Bashar al-Assad was sworn in Wednesday for a new seven-year term in a red carpet ceremony in Damascus, after an election his opponents had slammed as a "farce".

Mr Assad swore by the Quran before the country's parliamentarians in an extraordinary session, 40 months into a conflict estimated to have killed more than 170,000 people.

"Syrians, three years and four months... have passed since some cried 'freedom'," he said, referring to the start of a March 2011 revolt that demanded his ouster.

"They wanted a revolution, but you have been the real revolutionaries. I congratulate you for your revolution and for your victory," Mr Assad told his supporters.

"Those who lost their way can now see clearly... the monstruous faces have been unveiled, the mask of freedom and the revolution has fallen." More than 1,000 people were invited to the inauguration ceremony, with Mr Assad arriving at the presidential palace in a black sedan car before being met on a red carpet by a military band.

Parliamentarians and other guests cheered for Mr Assad in the hall where he was sworn in and then gave a speech.

Mr Assad won a June 3 election held only in regime-controlled territories by 88.7 per cent, defeating two other candidates seen as figureheads, rather than genuine opponents.

The opposition National Coalition branded the election a "farce" even before it was staged, in a statement later echoed by US Secretary of State John Kerry and Nato chief Anders Fogh Rasmussen.