Syria’s Defence Minister Daoud Rajha has been killed by a bomb attack on the headquarters of the National Security Bureau in Damascus.

The blast also killed Assef Shawkat, the brother-in-law of Syrian President Bashar al-Assad. The attack occured during a meeting on 18 July in the security headquarters building, located in the Rawda district of the Syrian capital. Intelligence chief Hisham Bekhtyar and Interior Minister Mohammad Ibrahim al-Shaar are also reported to have been injured in the explosion.

The bomb attack is the latest of several violent confrontations in the Syrian capital. On 16 July, in response to an increasing presence of opposition forces in Damascus, Al-Assad ordered the largest deployment of troops in the capital since the uprising against his rule began in March 2011 in order to try and crush opposition to his rule.

Escalating violence led to the International Committee of the Red Cross (ICRC) saying on 15 July that Syria had now slipped into civil war. As a result of the declaration, those involved in the violence will be now subject to the Geneva Conventions and could face war crime prosecutions for any actions deemed illegal.

Meanwhile, the UN is preparing to vote on fresh sanctions against the Al-Assad regime. A draft resolution drawn up by Western states calls for the Syrian regime to withdraw heavy weaponry from urban areas and return troops to military bases, or face sanctions. Any sanctions against the Al-Assad regime will require the support of China and Russia, who have so far refused to intervene in the conflict.

The UN has until 20 July to renew the mandate for its observers in Syria, which first entered the country in April to oversee a six-point peace plan proposed by the UN-Arab League ambassador to Syria, Kofi Annan. Activists claim that more than 16,000 people have been killed in Syria since the uprising began.