A suicide bomber riding a motorcycle has attacked a police checkpoint in northwestern Pakistan, killing 13 people and wounding 12.

The bomber attacked a crowd on Wednesday that was gathered along the road to greet Maulana Fazlur Rehman, a prominent hardline Islamist politician, said Saeed Khan, a police official at the main communications center in Peshawar city.

The attack occurred in Swabi town, located 70km outside the capital, Islamabad. "Rehman, the leader of the Jamiat Ulema Islam party, passed through the checkpoint only minutes before the bomber struck and was unharmed," said Khan.

"The bomber detonated his explosives just outside the checkpoint when a policeman told him to halt," Khan added.

It was unclear if the bomber specifically targeted the supporters of Rehman or if they just happened to be there when the bomber hit the checkpoint.

Rehman has been an outspoken supporter of the Afghan Taliban, but some militants in Pakistan have shown a willingness to attack anyone connected to the government.

No group has claimed responsibility for the bombing.

Source: Agencies