Those dead and wounded in the attack included police and civilians [Reuters]

At least 13 people have been killed and 20 others injured after a suicide bomber hit a minibus carrying police cadets in eastern Afghanistan, a government spokesman has said.

The attack took place at around 4:45 pm (1215 GMT) in the eastern province of Nangarhar, just outside the city of Jalalabad.

Ahmadzia Abdulzai, a spokesman for the governor of Nangarhar province, said a suicide bomber drove an explosives-packed car into the bus carrying the cadets.

"It was a suicide attack against a small bus carrying Afghan police," Abdulzai told Reuters news agency.

"The dead and wounded include police and civilians."

The attack was claimed by the Taliban. Its spokesman Zabiullah Mujahid said: "One of our mujahedeen carried out a martyrdom attack on a bus carrying police trainers in Nangarhar province today.

"The bus was totally destroyed and 25 police trainers were killed. Unfortunately, two civilians were also martyred."

Deadly protest

The attack came on the same day that 12 people died during a violent protest in Takhar province, northeast Afghanistan, against a NATO-led raid which left four people dead.

President Hamid Karzai, who condemned the NATO operation, said the four dead were civilians.

But the International Security Assistance Force (ISAF) said they were "insurgents".

Violence across Afghanistan last year hit its worst levels since the Taliban were ousted by US-backed Afghan forces in late 2001.