A motorcycle bomb attack on Wednesday near a Shiite Muslim shrine southeast of Damascus killed at least eight people and injured dozens, a watchdog said.

State television confirmed the blast, but said that six people had died and 13 were injured.

"At least eight people were killed and dozens were injured when a bomb planted in a motorcycle exploded outside the Yasser hotel, near the Shiite shrine of Sayyida Zeinab," said the Syrian Observatory for Human Rights.

"A police source in Damascus province said an armed terrorist group set off an explosive device hidden in a rubbish bag... in the Sayyida Zeinab area," said state news agency SANA.

The Sayyida Zeinab area has seen frequent violence in recent months, including a suicide bomb attack on June 14 that injured 14, according to state media.

The neighbourhood is disputed between rebels and the army.

It is home to the mausoleum of Sayyida Zeinab, the granddaughter of the Muslim Prophet Mohammed and is considered holy by Shiite Muslims.

On August 5, rebels fighting to oust President Bashar al-Assad's regime posted a video online saying they had kidnapped 48 Iranians from the area, charging they were elite Revolutionary Guards.

They said three of them died a day later in government shelling.