A suicide bomber has killed the head of a paramilitary police force and at least two others in northwestern Pakistan.

Pakistani officials say Sifwat Ghayur, the head of Pakistan's Frontier Constabulary, died in the attack Wednesday in the city of Peshawar.  They say at least 11 others were wounded in the blast.

Officials say the bomber approached Ghayur's vehicle on foot and detonated his explosives.  The blast ripped through several other cars nearby.

The Taliban has claimed responsibility and threatened to carry out more targeted assassinations.

The blast comes as the area struggles to recover from more than a week of devastating floods that have killed 1,500 people and affected millions of others.

In Washington, U.S. Secretary of State Hillary Clinton expressed condolences for the attack.  Clinton said violence like this is abhorrent at any time, but especially at this time of crisis.  

Meanwhile in the southern port city of Karachi, violence erupted for a second straight night, killing at least 13 people.

Protesters burned cars and shops and gunned down people, bringing the two-day death toll to at least 62.

The violence was sparked by the assassination Monday of provincial lawmaker Raza Haider, a member of the Muttahida Quami Movement.

Pakistani officials have blamed Haider's assassination on Taliban-linked militants trying to fuel political tensions.  But leaders of the MQM, which represents Karachi's majority Urdu-speaking community, blamed a rival political force -- the Awami National Party, or ANP, which is a representative of Karachi's ethnic Pashtuns.

The two parties have routinely blamed each other for deadly attacks on their activists.  Politically motivated violence this year has left nearly 200 people dead in Karachi.

Some information for this report was provided by AP and AFP.