However, the ministry of defense pledged tough response for the once-unthinkable bold attack.

In a statement carried by the state-TV, the ministry pledged to eradicate the armed groups and their hideouts, adding that the recent attack will only strengthen the forces' resolution to eliminate the terrorists across the country.

It said that he who thinks he would twist the arm of the administration by killing top officials is "delusional."

Meanwhile, an Islamist extremist group reportedly claimed responsibly for the attack, while the head of the Syrian opposition forces, based in Turkey, said his militia will carry on more attacks.

Information Minister Omran Zoebi said the morale of the Syrian army is high, refuting media claims circulated on Arab TV which said that the spirit of the Syrian army is low and that many defections have happened after the blast.

He said that Syria is capable of retaliation, adding that what happened is the work of the countries which support the armed groups in Syria with money and arms. Just a couple of hours after the blast, a new defense minister, Fahad Jassim al-Freij, was appointed by Assad.

Wednesday's attack came just hours before the meeting of the UN Security Council, which is set to discuss the rival texts of two resolutions put forward respectively by Russia and Britain.

Moscow said on Monday that Western governments are trying to blackmail Russia into supporting their draft of the Syrian resolution, threatening to end the UN observer mission if a deal is not reached.

The Britain-proposed UN resolution calls on the Syrian government to pull out troops and heavy weapons from populated areas within 10 days otherwise Syria would face non-military sanctions. However, the resolution is demanded to be adopted under the chapter 7 of the UN charter, which would allow the resolution to be imposed militarily.

Russia has expressed opposition to the new resolution, and called for extending the mission of the UN Supervision Mission for another three months.

The brazen bombing has come also as the capital Damascus is witnessing a surge in clashes between the government troops and the armed rebels, who are expressing unwavering support to bring down the capital.

The rebel Free Syria Army said the "greater battle" of Damascus has already begun and they have used a new tactic to launch a number of simultaneous attacks in many areas and reportedly set tires ablaze to scatter the Syrian army's attention.

However, well-informed sources told Xinhua recently that hundreds of armed men have been killed since Sunday, when the capital's military showdown started.