A suicide attack on an election rally for the Awami National Party (ANP) on Tuesday killed Pakistani journalist Aslam Durrani, news editor of the Urdu language Daily Pakistan.

Two other journalists, Durrani’s colleague Azhar Ali Shah and Express News reporter Ihtesham Khan, were injured in the attack, according to reports by the Karachi-based Express Tribune.

The rally was attended by Senior ANP leader and former federal minister for Railways, Ghulam Ahmed Bilour. The Pakistan news website dawn.com reported that he was not the target of the attack.

The outlawed Tehrik-i-Taliban Pakistan (TTP), which claimed responsibility, said that the intention behind the bombing was to kill Ahmed Bilour’s nephew, Haroon Bilour.

Haroon is the son of another ANP politician, Bashir Bilour, who was killed in an attack in 2012, reports said.

Photographs showed Ahmed Bilour escaping the scene with only minor bruises, but with his clothes spattered with blood after the bombing.

As the country approaches a historic vote on May 11, an election that will replace the first civilian government that has finished its term without being ousted by the military, the security situation during electoral rallies has become fragile.

AFP reported that Tuesday’s attack, which killed 20 people and injured dozens more, is one of the bloodiest incidents in this year’s run-up to the election.

It was the fourth deadly attack on politicians or political parties in the last three days.

Parties like the ANP, which Islamic extremist groups accuse of promoting a secularist agenda, have repeatedly been the target of terrorism.

Durrani is the sixth journalist to be killed this year in Pakistan. According to IPI’s Death Watch, in 2012 Pakistan was the most dangerous country for media workers in Asia and the third most deadly country for the media worldwide, trailing only war-torn Syria and Somalia.

“We call on the Pakistani authorities to help ensure the safety of journalists covering the upcoming elections” IPI Deputy Director Anthony Mills said. “In particular, the perpetrators of attacks against journalists must be held to account, to roll back the cycle of impunity that is fuelling further attacks.”