A bomb attached to a bicycle killed at least five people in volatile northwestern Pakistan on Monday morning. Area police chief Saeed Ullah said the attack in Dera Ismail Khan also wounded several people. Ullah refused to speculate on the motive behind the attack. Dera Ismail Khan lies in a region that neighbors the Waziristan tribal areas, where Taliban and al-Qaida terrorists have strong sway. But the city also has been the scene of sectarian violence in the past.