Syrian defence minister Dawoud Rajha Dawoud Rajha, Syria's defence minister, and Assef Shawkat, President Bashar al-Assad's brother-in-law and a key regime figure, were among those killed in a bomb blast in Damascus on Wednesday, state television reported. Later reports from Lebanon's Hizbollah-controlled TV station, al-Manar, which is close to the regime in Damascus, claimed that Gen HassanTurkmani, a former minister of defence and former army chief of staff, had died of his wounds in the attack, which struck at the heart of the regime. A fourth senior regime figure, the interior minister Mohammed Ibrahim al-Shaar, was also injured and there were conflicting reports on the status of Hisham Bekhtyar, the head of intelligence services. Mr Shawkat was the deputy head of the Syrian armed forces. Claims that Mr Assad himself had been at the meeting were discounted by a former regime adviser who told the Financial Times that the president did not usually attend meetings of the security council. There were further reports of military action at key points in the Syrian capital. Reuters quoted residents as saying they heard five explosions near or in the headquarters of the 4th Armoured Division, just to the south of Damascus. That unit is regarded by analysts as integral to the regime's grip on power and is commanded by Maher al-Assad, the president's brother. Leon Panetta, the US defence secretary, said that Mr Assad's refusal to step down meant that "the violence there has only gotten worse and the loss of life has only increased, which tells us that this is a situation that's rapidly spinning out of control." Sergei Lavrov, the Russian foreign minister, was quoted by the RIA Novosti news agency on Wednesday accusing the west of inciting rebel forces. "Instead of calming the opposition down, some of our partners are inciting it to go on," he was quoted as saying. Meanwhile, William Hague, the UK foreign secretary, condemned the bombing and said it demonstrated the need for implementation of a peace plan being led by Kofi Annan, the former UN secretary general. Government sources were reported as saying that army troops had killed many rebels in the capital. Activists close to the Free Syrian Army, the main rebel group, denied this, insisting that the perpetrator was someone with access and who was co-operating with them, and had escaped safely. Louay Mokdad, an activist who works with the FSA, said the regime wanted to portray the explosion as a suicide attack by jihadis to reinforce its narrative of the conflict, but he insisted that it was an operation by the Free Syrian Army, with help from insiders. He said rebels have been saying that the presidential palace and other top security sites are targets. "We have been saying to him (Bashar al-Assad) leave now or you will never leave alive," said Mr Mokdad. Another activist said that the FSA had originally intended to blow up the presidential palace. Syrian officials interviewed on the Hizbollah television station insisted that the attack, while damaging, would not mark the unravelling of the regime. However, the attack underlines that the regime's inner circle is no longer secure and raises questions about the loyalty of those charged with its security. Fierce clashes erupted in a series of districts, including Midan, Qaboun and the suburb of Harasta, activists said, as residents reported a patchwork of heavy fighting in some parts of the capital and relative calm in others. The violence in the capital, the most intense since the start of the 16-month-old uprising, comes as the UN Security Council prepares to vote for a third time on a resolution threatening sanctions against the Assad government. An activist named Elias said the Free Syrian Army hit a building close to the presidential palace in west Damascus with a rocket-propelled grenade overnight. "We can hit everywhere in Damascus," Elias said. Rebels claimed that they shot down a helicopter over the long-rebellious Damascus district of Qaboun on Tuesday, as fighting raged in other districts including the central area of Midan. The claims are hard to verify.