Twin suicide attackers targeted a police station in central Damascus on Tuesday, killing at least 14 people as the Syrian army launched multiple attacks on rebel positions in the northern province of Aleppo.

The blasts wounded more than 30 people, state media and the Syrian Observatory for Human Rights watchdog said.

They caused widespread damage in the central Marjeh neighborhood, with state television broadcasting images of blood and broken glass on the pavement near the scene.

A view shows the site after bombs exploded close to a police post in the central Marjeh Square in Damascus, June 11, 2013, in this handout photograph distributed by Syria's national news agency SANA. [Photo/Agencies]

"The number of casualties after a twin suicide attack in Marjeh Square has risen to 14 dead and 31 injured," said the channel, updating an earlier number.

"The two suicide explosions took place near a police station," it said.

The channel broadcast interviews with civilians at the scene of the attack.

"God take revenge on those who are behind this ... People were just sitting in their homes, or in their shops," said an unidentified shopkeeper, unable to hold back his tears.

"God take revenge against all those who are destroying this country," he said.

"It's criminal ... Look at the corpses, look at the blood," said another, who appeared to be in a state of shock.

State media had earlier said the bombs had been left outside shops in Marjeh Square, located in the heart of the Syrian capital, which has been rocked several times since the war between government forces and rebels began.

Marjeh Square was scene to previous attacks earlier this year.

A bomb attack in the same square six weeks ago killed 13 people. Since then, Syrian President Bashar al-Assad's forces have retaken rebel-held areas to the east of the capital and also driven rebels from their stronghold in the town of Qusair, close to the Lebanese border.

The Syrian Observatory for Human Rights also reported the blasts, but put the toll higher at 15 and said most of the casualties were police.

One of the blasts "was caused by a suicide bomb attacker who blew himself up inside the police station", said the Britain-based monitoring group.

"A second explosion took place just outside the police station," the group said, without elaborating on the nature of that blast.

"The number of casualties is expected to rise because several of the wounded are in a critical condition," added the Observatory, which relies on a network of activists, doctors and lawyers for its reports.

There was no immediate admission of responsibility, but car bombs and suicide attacks targeting Damascus and other cities that remain under government control have been claimed in the past by the al-Qaida affiliated Jabhat al-Nusra - one of scores of rebel factions fighting the forces of President Bashar al-Assad.

On Saturday, a suicide bomber detonated his explosives-laden car in the central city of Homs, killing seven people.

AFP-Reuters-AP