Afghan policemen carry the dead body of a guard from the scene of a suicide attack in Wazir Akbar Khan district of Kabul.

Kabul, Afghanistan -

Two men wearing suicide vests blew themselves up near a US base in the Afghan capital early on Wednesday, killing two Afghan guards in what looked like a thwarted attempt to attack the American base, police said.

The blast reverberated around Kabul's Wazir Akbar Khan neighbourhood shortly after 8am local time. An alarm started going off at the nearby US Embassy, warning staff to take cover. The neighbourhood also is home to many high-ranking Afghan officials, international organisations and the headquarters of the international military coalition.

The Taliban claimed responsibility for the bombing in an email to reporters.

The attack came as foreign and Afghan forces tightened security around the capital ahead of the holy day of Ashoura on Saturday, when Shi'a Muslims commemorate the seventh century death of Imam Hussein, the Prophet Muhammad's grandson.

Last year, the commemoration saw the first major sectarian attack since the fall of the Taliban regime. In that strike, a suicide bomber on foot detonated his vest amid scores of worshippers at a Shi’a shrine, killing 56 people and wounding more than 160 others.

Wednesday's bombers were on foot and were spotted by Afghan security guards as they approached Camp Eggers, the Kabul police chief's office said in a statement. The police fired on the attackers and they detonated their vests. Two Afghan security guards were killed and five civilians were injured in the explosion, the statement said.

Associated Press video of the scene shows what looks like an undetonated suicide vest, suggesting not all the explosives went off.

An international coalition vehicle was also damaged in the attack but there were no initial reports of casualties among the foreign forces, said Jamie Graybeal, a NATO troops spokesman.

Police had already set up extra checkpoints around Kabul and specifically near shrines to search cars and people in the run up to the Ashoura.

“All our police units are in the first security alert position,” General Mohammad Daoud Amin, the city's deputy police chief, said Tuesday, the day before the Kabul attack. “We are at the service of the people and doing our best to provide good security and prevent any possible incident on Ashoura.” - Sapa-AP