Malik Muhammad Ishaq, the chief of Sunni terrorist group Lashkar-e-Jhangvi (LeJ), and his two sons were killed in a police shootout in Punjab province of Pakistan on Wednesday.

Malik Ishaq, his two sons Usman and Haq Nawaz, and eleven others were killed in an alleged exchange of fire with police personnel in the Muzaffargarh district in early Wednesday morning. 

The shootout took place when Lashkar-e-Jhangvi militants tried to free him in an attack on a police party, reported Geo News. Malik and his associates were arrested last week by the police.

The Counter Terrorism Department (CTD) officials said more than 12 gunmen freed Ishaq and his associates from their custody when they were returning after making an explosives' recovery in Shahwala area, reported Pakistan Today. Security forces gunned down 14 militants, including Ishaq, in retaliatory fire.

"After the recovery when police were returning back, at around 3:00 a.m., more than a dozen terrorists attacked the convoy and tried to rescue Ishaq and others," police officials said, according to Geo News.

"The police retaliated and in the encounter Ishaq and his two sons were killed," police said. Six police personnel also injured in encounter.

Malik Ishaq's killing triggered tension in some parts of Punjab province, particularly his hometown of Rahim Yar Khan, reported Express Tribune. LeJ supporters attacked a police van and organized a protest in his hometown.

Malik Ishaq was arrested in 1997 and is charged with masterminding dozens of attacks on the Shia community. He was released in 2011. He was arrested again in 2013 over deadly sectarian attacks targeting the Hazara Shia community in Quetta, according to Dawn.

The Lashkar-e-Jhangvi has claimed responsibility for two suicide bombings in Quetta in early 2013 that killed more than 180 people, belonging to Shia minority. The banned Sunni extremist outfit, responsible for some of bloodiest attacks on Shia community in recent history, is also credited with carrying out an attack on the Sri Lankan cricket team in Lahore in 2009 which wounded several players.