Beirut: A powerful blast from explosives planted in a tunnel under the Old City of Aleppo, in northern Syria, killed or wounded 20 government troops on Tuesday, a monitor said.
Jabha Shamiyeh, a new rebel coalition in Aleppo, was behind the blast, said the Syrian Observatory for Human Rights, which was not immediately able to give a breakdown of the dead and wounded.
The explosion "killed and wounded at least 20 troops and loyalists," said the Observatory, which relies on a broad network of sources for its reporting.
The Britain-based group said Jabha Shamiyeh "carried out a tunnel blast targeting positions and bases that belong to regime troops and pro-regime militia" in the Old City.
Jabha Shamiyeh, formed less than a week ago, has not claimed responsibility, but opposition activists in Aleppo said it was behind the explosion.
For its part, state television said "terrorist groups targeted the Old City with three blasts, west of the citadel... Destroying several historic buildings in the area."
The channel, using the regime's term for rebels, did not report any casualties.
A Syrian military source in Aleppo, speaking on condition of anonymity, confirmed to AFP that rebels had detonated a tunnel dug underneath a building.
Meanwhile, clashes broke out, said the source, who added: "The army managed to repel a (rebel) bid to carry out an offensive."
Fighting in Aleppo erupted in mid-2012, and control of the
City has since been divided between rebels on the eastside and the regime in the west.
Violence has devastated parts of the famed Old City.
In May, rebels detonated explosives under the famed Hotel Carlton, which government forces had been using as a base.
In September, several other buildings were destroyed in a similar tunnel attack.