AMMAN: A bomb killed at least six people on Wednesday near a Shi'ite shrine in a suburb of the Syrian capital Damascus, state media and opposition activists said.

State media said 13 people were also wounded in the explosion in the Sayeda Zainab district. The semi-official Addounia television said the bomb was placed in a garbage bag. Another bomb in the area was defused, the station said.

"The explosion occurred just east of the shrine. Lots of people are also wounded," said one of the activists in the area, who declined to be named.

"Security personnel have swarmed the area. It is not clear whether the target was the shrine or a security compounding adjacent to it," he added. Groups opposed to President Bashar al-Assad say seven people died in the blast.

The poor neighbourhood, inhabited by a mix of Sunni and Shi'ite Muslims, is marked by the coloured tile and mirror shrine, located near several security compounds, as well as an office for Shi'ite Iraqi cleric Muqtada al-Sadr.

Concern among Shi'ites and moderate Sunnis have been rising that Sunni zealots could target the shrine for Zainab, the Prophets' granddaughter and daughter of the Caliph Ali, who is highly revered by Shi'ites.

As the 19-month revolt against Assad turns bloodier, sectarian tension has increased between members of the country's Sunni Majority and Assad's Alawite sect, an offshoot of Shi'ite Islam that has dominated power in the country since the 1960s.