Damascus: A massive bomb blast rocked the heart of Damascus on Wednesday as pressure mounted on the regime, with world's largest pan-Islamic bloc poised to suspend Syria over the unrelenting violence.

The United States also accused Iran of setting up a pro-regime militia in Syria as Washington increasingly ties the conflict that is now in its 18th month to interference by its long-time foe Tehran.

A bomb ripped through a petrol tanker outside the Damascus hotel used by the UN observer mission in Syria and a military headquarters, state television reported, adding that three people were wounded.

The Free Syrian Army claimed the attack, saying it targeted a regular operational meeting of military officers and members of the pro-government shabiha militia.

Television footage showed the tanker with its rear-end blown out and the smouldering and blackened wreckage of at least one other vehicle, as firefighters doused the flames and security forces set up a cordon at the area.

It was the latest in a series of bomb blasts that have rocked the city since President Bashar al-Assad's regime launched a brutal crackdown on dissent in March last year, including an attack that killed three top security chiefs.

Meanwhile, the Organisation of Islamic Cooperation, which represents 1.5 billion Muslims worldwide, was poised to suspend Syria at an emergency summit on Wednesday in a move opposed by Iran, a staunch ally of Assad's increasingly embattled regime.

The move by the OIC is aimed at further isolating Assad's regime over a conflict that activists say has now claimed over 23,000 lives, but its effect is seen as largely symbolic.

Syria was suspended from the Arab League last year over its crackdown on the Arab Spring-inspired uprising that Assad has characterised as a plot by Western and rival powers to overthrow his regime.

A final draft statement says Syria should be suspended over "the obstinacy of the Syrian authorities in following the military option" to solve the crisis and the failure of a UN-Arab League peace plan brokered by Kofi Annan.

It demands that Assad's regime "immediately end all acts of violence" while defending Syria's "unity, sovereignty, independence and territorial integrity."

Tensions have been simmering for months between Sunni-dominated Saudi Arabia and Shiite-dominated Iran as Syria has emerged as another arena for the longtime rivalry between the two regional heavyweights.

(Agencies)

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