Moscow, July 18 (IANS) Syrian Defence Minister Daoud Rajha and his deputy, Assef Shawkat, who was also President Bashar al-Assad's brother-in-law, were killed Wednesday in a suicide bombing in the capital city of Damascus, state media reported.

The blast occurred during a meeting of ministers and security officials at national security headquarters, RIA Novosti reported.

Citing Syrian state TV, Xinhua said Interior Minister Mohammed Ibrahim al-Shaar, who was also injured in the bombing, was still alive but in a critical condition.

BBC said the rebel Free Syrian Army (FSA) and a jihadist group calling itself Lord of the Martyrs Brigade both claimed they were behind the bombing.

Lebanon's al-Manar TV reported that the interior minister died from his wounds.

The government later appointed General Fahad Jassim al-Freij as the country's new defence minister.

The Free Syrian Army said earlier this week it had launched the final battle for Damascus, which had so far seen little of the violence that has claimed thousands of lives across Syria.

The 15-member UN Security Council will vote later Wednesday on a new Western-backed resolution on Syria which could lead to tough new sanctions against Assad's regime.

Russia has said it will block the resolution and has called for all sides in the conflict to implement UN special envoy Kofi Annan's floundering peace plan.

Security sources told BBC the suspected bomber in Wednesday's attack worked as a bodyguard for members of Assad's inner circle.

Rajha had been defence minister for less than a year, serving previously as chief of staff, and was on a US blacklist for his role in the suppression of dissent.

He was an Orthodox Christian - a rarity in the Syrian military and government.

Shawkat was considered a top security chief and a member of the inner circle of the regime. He was married to Assad's sister Bushra.

Citing state media reports, BBC said Hisham Ikhtiar, director of the National Security Bureau, was among the injured.