Damascus: A bomb planted under a diesel tanker on Wednesday went off and wounded at least three people in this city near the Syrian Army headquarters and the Dama-Rose hotel, where the UN observers are residing, the state TV said.
The blast sent plumes of black smoke into the sky, the TV said. Medical staff were seen on the spot to rescue the injured.
It wasn`t immediately known who had managed to carry the bomb to the heavily fortified area, which has been ringed by blast walls and checkpoints.
No UN monitors were reportedly injured in the attack.
The monitors are on an observing mission in Syria, which has been suffering from bloody conflicts between the government and opposition forces, to seek a peaceful settlement between them.
Media reports said the explosive device ripped through the diesel container while it was parked at one of the Army headquarters` garages.
Sharif Shahadeh, a Syrian parliamentarian, when talking to al-Jazeera TV, claimed the armed opposition group had carried this "terrorist" attack.
Last week, a bomb tore through the state media establishment on the Ummayad square, which is also in the surroundings of the Army headquarters, and caused injuries.
Such blasts, despite their small scopes, are a show by the defiant armed opposition that it has a long reach and can foment anarchy anywhere.
On the ground militarily, the armed opposition has been taking pains to make footholds in Damascus and most recently in the northern Aleppo province.
The Syrian Army`s strong offensives have pushed the rebels to frequently resort to guerrilla tactics or bomb attacks.