Kabul, May 4 (IANS): Three people died and 21 were injured in Kabul on Monday when a suicide attacker blew himself up while a bus carrying government employees was passing by, official sources told Efe news agency.

The attack occurred around 8.30 a.m. to the west of the Afghan capital, said the police emergency department's chief Humayun Aini, adding that the bus was carrying employees of the attorney general's office.

Afghanistan's health ministry spokesperson Ismail Kawusi confirmed to Efe that 21 people were hospitalised while two civilians and the perpetrator of the attack were killed.

The Taliban claimed responsibility for the attack using the official Twitter account of their spokesperson Zabihullah Mujahid who claimed that the attack killed and injured more than 40 officials, though the insurgents often exaggerate the result of their actions.

This is the first Taliban attack in Kabul since the beginning of the spring offensive on April 22 and comes amid ongoing peace negotiations between government representatives and insurgents in Qatar.

The end of 2014 saw the termination of NATO's International Security Assistance Force (ISAF) mission in Afghanistan, making way for Operation Resolute Support, under which NATO maintains around 4,000 soldiers to train Afghan security forces.

The US has about 11,000 soldiers in Afghanistan under its anti-terrorism combat mission, where they will remain until 2016, while Washington is re-evaluating its withdrawal time frame.