Islamabad: Pakistani investigators scouring the scene of a weekend suicide bomb attack on police found a severed head on Monday as the leader of the ruling party said his government would do everything to stop the bombers.

As police were investigating the Sunday blast in the capital, six small bombs went off on streets in the southern city of Karachi.

At least 23 people were wounded in the blasts on Monday, police said. No one claimed responsibility for the bombings.

"These blasts were meant to create harassment among the people," city police chief, Waseem Ahmed, told state television.

Provincial interior minister Zulfiqar Mirza said five of the bombs had gone off in ethnic Pashtun neighbourhoods.


Meanwhile, the toll from Sunday's attack on police, who had been guarding Islamists marking the anniversary of an army commando raid on Islamabad's Red Mosque, rose to 18 as two more of the nearly 50 wounded died, police said.

Investigators at the site discovered a severed head in bushes by the road where the attack took place, according to media reports, but police declined to comment on the grisly find.

Police investigator Falak Sher said an estimated 5 kg of explosives had been used in the attack.

"We've spoken to the wounded but haven't been able to get any solid clue that can help make a sketch of the bomber," Sher said.

The blast happened several hundred metres from the city centre's Red Mosque, shortly after a tightly guarded meeting of Islamists there had ended.