BEIRUT An explosion struck the Christian Bab Touma district in the Old City of Damascus on Thursday in what Syrian state television said was a suicide bombing. Opposition sources said it was a mortar attack.
It was the first major blast reported inside the walls of the Old City, a UNESCO World Heritage site that is one of the oldest cities in Middle East, dating back some 4,000 years.
At least four people were killed and several wounded, Syrian television said. News outlets close to rebels fighting to topple President Bashar al-Assad said a mortar bomb had exploded.
The Syrian Observatory for Human Rights, a pro-opposition monitoring group, said two mortar rounds had hit Amin Street, home to Shi'ite Muslim families who generally back Assad.
It was unclear who was behind the attack, but there were many potential targets in the vicinity.
One was the ancient Mariamite Cathedral, seat of the Greek Orthodox Church of Antioch, which like most churches has avoided announcing a stance on the 27-month-old struggle between President Bashar al-Assad and mostly Sunni Muslim rebels.
The church is near the cobblestone Roman "Straight Street" that runs past many old buildings and a luxury restaurant once frequented by Assad and his inner circle.
Syria's minorities, especially Assad's Alawite sect, an offshoot of Shi'ite Islam, have generally stood behind the president during the conflict in which the Syrian Observatory says more than 100,000 people have been killed.
Christians had tried to remain neutral but increasingly their young men have been joining pro-Assad militias blamed for some of the worst attacks against the opposition.
The Old City is the historic heart of Damascus. Before the war, it drew crowds of tourists to its souks, monuments, religious sites, restaurants and craft shops.
Syria has been in turmoil since an initially peaceful uprising against four decades of Assad family rule turned into a civil war increasingly fought on sectarian lines.