Officials in northwest Pakistan say a female suicide bomber has detonated her explosives near the convoy of a former leader of the country's largest Islamist political party.

Authorities say the target of the blast was Qazi Hussain Ahmad, the former head of Jamaat-e-Islami, who was unharmed in the explosion.

However, at least three of the political party's workers were wounded in the incident in the Mohmand tribal region.

No group has claimed responsibility for the attack.