Ancient Syrian Market Burns As Fighting Rages

Deadly clashes have intensified in Syria's largest city Aleppo where fighting sparked a fire that ripped through a medieval souk.

Fighting between Syrian rebels and forces loyal to President Bashar al Assad killed at least five people in the embattled northern city, the London-based Syrian Observatory for Human Rights said.

The fighting in Aleppo was accompanied by intense overnight shelling that continued into the morning. Several homes were also destroyed in the violence, the Observatory said.

Aleppo, Syria's most populous city, has been the main battleground for the past two months of the country's 18-month conflict, and has been gripped by fighting on an unprecedented scale in recent days.

Much of the violence has centred on the Old City, and is believed to have sparked a fire that has been burning for two days now in the centuries-old souk marketplace  - one of the best-preserved bazaars in the Middle East.

It was the worst blow yet to the city's historic centre and to a UNESCO World Heritage site in Syria.

Amateur video showed wall-to-wall flames engulfing wooden doors as burning debris fell away from the storefronts. Activists said hundreds of shops were affected.

Clashes were also reported elsewhere in the northern province of Aleppo, where rebel mortar fire damaged two helicopters at the Al-Nairab military airport.

Syria's state news agency says Assad's troops have carried out a "successful operation" in western Aleppo against "terrorist gatherings" - a reference to the rebel Free Syrian Army.

Elsewhere in Syria, the Observatory for Human Rights said a "strong explosion" rattled the northeastern city of Qamishli on the Turkish border.

It said the explosion appeared to be caused by a booby-trapped car but that it was not immediately clear whether there were any casualties.

The Observatory said a handful of civilians were killed in violence in Homs and other areas across the country.