At least 30 people have been killed and more than 100 injured in an explosion at a mosque during Friday prayers in Pakistan's capital, Islamabad, according to local officials.

An emergency was declared at the city's hospitals after the blast at a Shiite mosque in the Tarlai area of the capital. The district administration spokesman said on X that the number of injured had reached 169.

The cause of the explosion was not immediately clear, however reports have suggested it was carried out by a suicide bomber.

Pakistan's Prime Minister Shehbaz Sharif has condemned the incident, expressing "deep grief".

Islamabad's deputy commissioner Irfan Memon said on X that the death toll had risen to 31, while a police source told news agency AFP that the numbers were "expected to rise further".

One AFP photographer said they saw dozens of people arriving at hospital.