A bomb blast on a bus in Peshawar killed at least nine people yesterday, officials said, in the latest attack to hit Pakistan’s troubled northwest ahead of historic polls next month. The explosion occurred just hours after militants blew up the election offices of an independent candidate in the North Wazirstan tribal district fueling concerns that violence will mar general elections on May 11. “At least nine passengers have been killed and seven injured. Bomb disposal officials told me that it was a timed device,” Fazal Wahid, a senior police official told AFP. Another officer, Imran Shahid said police were investigating the possibility a suicide bomber was involved in the attack which occurred as the was bus passing through the city’s Matani suburb. There was no immediate claim for responsibility, but Peshawar is regularly targeted by the Pakistani Taleban who have waged an insurgency against the state since 2007. An intelligence official in the city said the attack may be a reaction to a fresh military push in the Tirah valley of the Khyber tribal district, where the army has been fighting Taleban and Lashkar-e-Islam militants. Military officials said heavy fighting between Pakistani troops and militants has killed 23 soldiers and 110 militants in Khyber this week. Khyber straddles the NATO supply line into Afghanistan, used by US-led troops to evacuate military equipment ahead of their 2014 withdrawal. Officials say securing Khyber is key to protecting security in Peshawar, ahead of elections which will mark the country’s first democratic transition of power after a civilian government has served a full term in office. Abdul Haq, a senior bomb disposal expert told AFP that four to five kilograms of highly explosive material was used. The bomb destroyed three shops and a motorcycle, police and witnesses said. In an earlier incident, militants blew up the election office of Kamran Khan, a former legislator from North Waziristan who supported the outgoing government led by the Pakistan People’s Party. No one was hurt. On Thursday, militants shot dead a candidate for outgoing coalition partner the Muttahida Qaumi Movement (MQM), the first to die in the election campaign, in an attack claimed by the Taleban. Pakistan says more than 35,000 people have been killed as a result of the country’s support to US in war against terrorism.