Islamabad, March 20 (IANS): Two people were killed and 20 others injured in an explosion during Friday prayers outside a Bohra community mosque in Pakistan's Karachi city.

Deputy Inspector General of Police Abdul Khaliq Shaikh said one person died instantly in the blast at Saleh mosque in Arambagh area, Dawn online reported.

One of the injured later succumbed to his wounds, police said. The dead were identified as Shabbir and Hasnain.

Shaikh said a timed explosive placed on a motorcycle went off.

The attack took place although security was, as a matter of routine, tightened on Fridays when mosques attract thousands of worshippers.

Condemning the attack, Sindh Chief Minister Syed Qaim Ali Shah sought a report from police.

It was the first attack in three years on a Bohra mosque in Karachi. The earlier one in 2012 killed seven people.

A large number of Dawoodi Bohra Muslims live in Pakistan, mostly in Karachi, Pakistan's biggest city.