LAHORE, Pakistan (Reuters) - Pakistani security forces said on Wednesday they had killed the leader of the banned Sunni Muslim militant group Lashkar-e-Jhangvi (LeJ) along with three other militants accused of killing hundreds of civilians.

The Counter Terrorism Department of the eastern province of Punjab said its forces had killed Asif Chotoo and his comrades during a shootout in the city of Sheikhupura after a tip-off that the group was planning an attack in nearby Lahore.

However, an intelligence official with knowledge of the operation told Reuters that Chotoo had been in custody since August and was “eliminated” by authorities, something Punjab police spokesman Nayab Haider called “baseless”.

The incident came 18 months after police gunned down Chotoo’s predecessor, Lashkar-e-Jhangvi’s longtime leader Malik Ishaq, in what police sources said bore halmarks of an “encounter”, a term government critics use for extrajudicial killings in custody staged to resemble a shootout.

Authorities deny any such practice exists.

The actions against LeJ, which targets minority Shi’ite Muslims, could signal a harder line against sectarian militants by a government regularly accused of being softer on them than on militants seeking to overthrow the government, such as the Pakistani Taliban.

LeJ was once believed to have support from Pakistan’s military intelligence agency, accused of using such groups as proxies in India and Afghanistan and to counter Shi’ite movements, something Pakistan denies.

Last week, opposition members walked out of parliament after Interior Minister Nisar Ali Khan said: “You cannot equate banned sectarian organizations with the banned terrorist organizations,” local media reported.

Pakistan banned dozens of militant groups under a National Action Plan, launched after Pakistani Taliban fighters killed 134 students at an army-run school in Peshawar in 2014.