Three killed in Karachi bomb attack

Local Pakistani residents gather at the site of the overnight bomb blast in Karachi on 15 March 2013
Image caption The blast took place near the office of a cable TV network, reports say

At least three people were killed and five injured after a bomb hit the Landhi neighbourhood of the Pakistani city of Karachi, officials say.

The blast took place near a police station. Media reports say it was also near the office of a cable TV network.

It comes as police arrested 20 people, including suspected members of banned militant groups.

Correspondents say it is a sign police are cracking down after a deadly blast killed dozens earlier this month.

Media reports quoting police say the bomb that went off in the early hours of Friday morning was remotely detonated.

Karachi has witnessed a deadly wave of violence in recent years.

At least 2,000 people were killed in the southern city in 2012, most of them in a string of targeted killings and deadly bombings.