A suicide bomb attack on a Shia Muslim mosque in the north-western Pakistani city of Peshawar has killed at least 14 people, police and officials say.

More than 20 people were also reported to have been injured by the blast, which happened during Friday prayers.

No group has yet said they carried out the attack.

In a separate incident, a provincial MP and his son were shot dead by unidentified gunmen as they left a mosque in the southern city of Karachi.

Sajid Qureshi was a member of the MQM party, which mostly represents the descendants of Muslim migrants to Pakistan at the time of the partition of India in 1947.

Police say that three people were involved in the Peshawar attack, including the suicide bomber and two armed accomplices, who shot a policeman before forcibly entering the mosque complex.

Witnesses say around 200 people were in the mosque at the time.

Police say the two accomplices escaped after the bomber detonated his explosive device, and a manhunt is underway in the Chamkani area of Peshawar.

Local TV reports later broadcast pictures of the mosque's blood-splattered floor and walls. Holes in the walls and ceiling caused by ball-bearings that were packed inside the bomb could be clearly seen.

The footage also showed distraught relatives helping to transport wounded victims, their clothes soaked in blood, to a local hospital.

Pakistan's Shia minority is the target of frequent sectarian attacks from Sunni militant groups who consider Shias to be heretics.

The mosque and seminary complex which were attacked are in Peshawar's Gulshan Colony, a Shia-majority area on the outskirts of the city.

Peshawar is close to militant strongholds in the north-western tribal belt, on the Afghan border.

On Saturday, twin attacks by militants in the city of Quetta killed 25 people. No clear motive for the attack was established, but a Sunni militant group was blamed.