A suicide bomber blew himself up at an anti-Taliban political party's rally in northwest Pakistan on Tuesday, killing 12 other people, including a candidate in July 25 elections, police said.

The attack on a meeting of the Awami National Party (ANP) in Peshawar also injured nearly 50 others, city police chief Jamil Qazi said. There was no immediate claim of responsibility for the attack, the first major pre-election violence.

The ANP was the main target of Taliban attacks in the 2013 election. Then, senior ANP leader Bashir Bilour was killed in a suicide bombing. Tuesday's attack killed his son Haroon Bilour, a candidate for the provincial assembly.