Pakistani police say they have placed a prominent Islamist militant under house arrest after accusing him of trying to incite sectarian hatred.

Officials say Malik Ishaq, the head of the banned Sunni Muslim extremist group Laskhar-e-Jhangvi, is under house arrest for 10 days in the city of Rahim Yar Khan. Police accuse Ishaq of making public sermons in recent months promoting violence against minority Shi'ite Muslims.

His arrest also comes days after gunmen killed 26 Shi'ite pilgrims traveling by bus through southwestern Pakistan on the way to Iran. And while suspicions fall on Laskhar-e-Jhangvi for the assault, police have not explicitly tied the group to the violence.

Authorities released Ishaq from prison in July after holding him nearly 14 years behind bars. He had faced accusations of masterminding numerous sectarian murders and organizing from jail the 2009 attack on the Sri Lankan cricket team in Lahore.

Also Thursday, Pakistani officials said a roadside bomb in the northwestern tribal belt hit a pickup truck carrying members of an anti-Taliban militia. Five people were killed.

Local government official Adalat Khan said Thursday's blast in Bajaur agency wounded eight others. He added that three of those who died were members of the anti-Taliban militia.

While the Pakistani military continues to battle militants throughout the northwest, Islamabad has long encouraged the formation of local militias, known as lashkars, to help in the fight against the Taliban, especially in remote areas near the Afghan border.

Members of the lashkars are often the targets of militant violence.