Blast on bus near Shi'ite shrine in Damascus kills six

DAMASCUS (Reuters) - A rare explosion in central Damascus targeted a bus believed to be carrying Lebanese Shi'ite Muslim pilgrims on Sunday, killing at least six people and wounding more than 20, a Reuters witness and local media said.

A social media account linked to al Qaeda's Nusra Front said the hardline Sunni group was behind the attack on the bus near a market place in the capital.

The vehicle had Lebanese number plates and Syrian security services had cordoned off the area close to Hamidiyeh market, the Reuters witness said.

Syria's state news agency SANA said the "terrorist explosion" had killed four and wounded 19.

The bus had been carrying pilgrims close to the Sayyida Ruqayya shrine, a television channel run by Lebanese Shi'ite movement Hezbollah said.

Syria's Ikhbariya television showed footage of men and a woman in hospital with wounds. It also showed footage of the blacked, wrecked bus and security services picking through the damage.

A Nusra Front Twitter feed said one of the group's members blew himself up inside a bus at the market. It posted a photo of a man it said was the bomber and another of the wrecked vehicle. Reuters could not immediately verify the images.

Nusra Front has been battling Syrian government forces as well as other insurgent groups in Syria. While fighting has raged on the outskirts of Damascus, attacks in the centre are relatively rare.

(Reporting by Marwan Makdesi in Damascus and Omar Fahmy in Cairo, Writing by Sylvia Westall in Beirut,; Editing by Andrew Heavens and Stephen Powell)