The revelation that a senior Pakistani army officer was detained on suspicion of ties to a radical Islamist group has raised fresh concerns about the reach and influence of an organization that has long vexed analysts and politicians. Hizb-ut-Tahrir says it rejects violence but uses venomous rhetoric and pushes for military coups. It seeks the overthrow of Pakistan's elected government and wants to unite the Muslim world under one government following strict Islamic law. Pakistan's army...

Pakistan's army spokesman says a senior officer serving at army headquarters has been detained for suspected links with a banned militant group. Maj. Gen. Athar Abbas said Tuesday that Brig. Ali Khan is being questioned by army authorities over the links. He said Khan was detained recently but did not provide an exact date or specify the banned militant group involved. The detention follows reports by U.S. officials that Pakistan detained five Pakistanis, including an army major, for helping...