A rare moment of contemplation for Syrian President Bashar al-Assad as he attends Eid prayers at a Damascus mosque.

The festival, which marks the end of the holy month of Ramadan, is traditionally a time of celebration in the Islamic world.

The besieged president, however, is battling an increasingly bloody 17-month uprising as his forces pursue an offensive against rebels.

Assad's government has also been forced to deny reports that his vice-president had joined the rebels, amid a string of high-profile defections.

Syrians who fled the bloodshed were also marking Eid in refugee camps in neighbouring countries, like this one in Jordan.

While children received gifts from aid agencies, for many, the mood was sombre.

SOUNDBITE) (Arabic) UNIDENTIFIED SYRIAN WOMAN, SAYING:

"There is no Eid in Syria. We want freedom and we do not want Bashar."

Celebrations were also muted in this refugee camp in Turkey where hundreds gathered for Eid prayers.

Some also met at the camp's cemetery to mourn the loss of loved ones.

More than 18,000 people have died and some 170,000 have fled Syria as a result of the fighting, according to the latest U.N. estimates.