Updated

Fighting between Syrian rebels and government forces killed at least five people in the embattled northern city of Aleppo, activists said Sunday.

The London-based Syrian Observatory for Human Rights said the dead included a man who has been shot by a sniper near the city's medieval citadel earlier in the day. Several homes were also destroyed in the violence, the Observatory said.

The country's commercial capital and largest city, Aleppo is home to some 3 million people and was once a bastion of support for President Bashar Assad. But the city has been hit by fierce fighting since rebels launched an offensive there in July.

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. SANA said several rebels had been killed or wounded in the violence, but gave no other details.

On Saturday, a fire sparked by battles between Assad's troops and rebels tore through Aleppo's centuries-old covered market, one of the best-preserved bazaars in the Middle East. It was the worst blow yet to the city's historic center and to a UNESCO World Heritage site in Syria.

The heightened violence in Aleppo drew criticism from the city's industrialists of "insufficient" government protection provided to factories and other businesses in the area.

Fares al-Shihabi, head of Aleppo's Chamber of Industry, told Syria's pro-government al-Watan daily that several previous calls on the government for increased protection against "daily armed attacks" on industrial estates "have gone unanswered."

In response, the chamber was forced to hire guards around-the-clock to protect the businesses against attacks by looters, he added.

Rami Martini, chief of Aleppo's Chamber of Tourism, warned of the vulnerability of tourist sites in the area. He told al-Watan that the violence in Aleppo has "dealt a blow in every sense of the word" to the country's tourism sector.

The Aleppo market, a major tourist attraction with its narrow stone alleys and stores selling perfume, fabrics and spices, had been the site of occasional gun battles and shelling for weeks. But amateur video posted Saturday showed wall-to-wall flames engulfing wooden doors as burning debris fell away from the storefronts. Activists said hundreds of shops were affected.

The souk is one of a half-dozen renowned cultural sites in Syria that have become collateral damage in the civil war.

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. In the restive southern town of Daraa -- the city where Syria's anti-Assad uprising began with peaceful protests in March 2011 -- tens of homes that belong to rebels were destroyed in the town of Mezereeb, the group added.