21 November 2012 Last updated at 03:31 ET

Suicide bomber kills two in central Kabul

The attack raises questions about security in the centre of Kabul

Two Afghan security guards have been killed and three wounded in a suicide attack in a heavily-guarded area of Kabul home to foreign embassies and Nato HQ, police say.

Two other people were injured in the blast in the Wazir Akbar Khan neighbourhood.

Police told the BBC that the attacker detonated his explosives near one of the entrances to a US military base.

The Taliban said that they were behind the attack.

High-profile attacks on Kabul

• 22 June 2012: At least 20 people die in Taliban attack on the Spozhmai Hotel near Kabul
• 15 April 2012: Seven sites including parliament, Nato HQ and foreign embassies attacked
• 29 October 2011: Suicide bomber attacks bus carrying Isaf staff, killing 13 foreigners and four Afghans
• 13 September 2011: Gunmen seize unfinished high-rise to fire on Nato HQ and US embassy
• 19 August 2011: Gunmen storm British Council HQ, killing 12 people
• 28 June 2011: 22 people die after militant attack on the Intercontinental Hotel

Kabul police chief Ayub Salangi told the BBC that the attacker had been shot and killed by the security guards, but not before he managed to detonate some of his explosives.

"The attacker wanted to get into a building under construction, and this is when he was shot by security forces,'' Gen Salangi said.

The BBC's Bilal Sarwary in Kabul says that the attack on Wednesday morning in the heart of Kabul raises several questions, including how the attacker managed to get inside one of the most secure and heavily guarded areas of the city.

The attack came as foreign and Afghan forces tightened security in Kabul ahead of the holy day of Ashura on Saturday, when Shia Muslims commemorate the 7th Century death of Imam Hussein, the Prophet Muhammad's grandson.

This time last year, a suicide bomber on foot killed at least 56 people at a Shia shrine in the city. More than 160 others were wounded, many of them later succumbing to their injuries.

Correspondents said it was the first major sectarian attack in Afghanistan since the Taliban were driven from power in 2001.