LAHORE: Punjab police said on Wednesday that suspected three militants involvement in Youhanabad church attack had been killed during a failed escape attempt.

Police sources claimed that they had taken the suspects to a village in the suburbs of Lahore to retrieve suicide vests and weapons, and came under attack as they returned.

“The attackers opened fire on police to try to release the terrorists. Police returned fire and the three militants were killed during the exchange of fire,” Haider Ashraf, a senior police official in Lahore, told AFP.

The trio were arrested along with two others on August 4 over the twin Taliban suicide attacks on two churches in Lahore's Youhanabad district in March that killed 17 people and wounded more than 70.

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Police said two officers were wounded in the clash with the attackers, who fled.

Punjab police spokeswoman Nabeela Ghazanfar confirmed details of the incident. In late July the detained leader of anti-Shia militant group behind some of Pakistan's worst sectarian atrocities was killed in a similar shootout.

Malik Ishaq was shot dead along with fellow Laskhar-e-Jhangvi (LeJ) militants, including senior commanders, in Punjab as his cadres tried to free him from custody, police said.

So-called “encounter” killings like Wednesday's incident and Malik's death have long aroused suspicion among rights activists in Pakistan. They say police use them to dispose of suspects without going through the courts.

The bombings occurred in March during prayers at two churches located around half a kilometre apart in Youhanabad, which is home to more than 100,000 Christians.

The attacks sparked two days of rioting by Christians who clashed with police, blocked roads and forced a partial shutdown of the city's public bus system.

At the time of the arrest, officials said the detainees belonged to a splinter group of the main Tehreek-i-Taliban Pakistan (TTP) faction.

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