Health officials in Pakistan say 44 people have been killed and 80 others wounded in an explosion at a political rally held in the country's northwest.

No one has claimed responsibility for the blast, which police suspect was a suicide bombing.

The explosion occurred on Sunday at the gathering of an Islamic party in a town near Pakistan's border with Afghanistan in the northwestern province of Khyber Pakhtunkhwa.

Police say the explosion was at a venue where more than 400 supporters of the party had gathered.

A person associated with the political group who was at the gathering told NHK a stage had been set up and speeches were being presented, when an explosion occurred near the stage.

Footage from a local hospital shows injured people being brought in one after another even though the interior was already crowded.

Political parties are stepping up their campaigns to appeal to voters as the term of the lower house of the national parliament expires in August.

The risk of terrorism tends to grow during election campaigning in Pakistan. In 2007, a suicide bomb attack killed former Prime Minister Benazir Bhutto, who was an opposition leader at the time.