Four suspected militants were killed during a raid carried out by Rangers personnel in Karachi's Urdu Bazaar area on Monday night, a press release issued by the paramilitary force said.

Lasting nearly seven hours, the 'targeted operation' ended at 2:45am on Tuesday, with one suspected militant shot dead in a shootout with Rangers and three other militants killed in suicide blasts. An infant was also killed in the fight.

The Rangers in a statement said they had previously arrested a "most wanted" militant of a banned outfit while acting on an intelligence report in Ittehad Town. On the information obtained from the suspect, Rangers personnel launched a raid in a building in Urdu Bazaar at 7:17pm on Monday.

Upon seeing the Rangers personnel, the suspected militants opened fire with automatic weapons and lobbed hand grenades, leaving four Rangers men and a boy, 12, injured.

When Rangers personnel surrounded the building, the four militants including a woman confined themselves to a room.

A shootout then ensued between the two sides and continued well into the early hours of Tuesday. During this time, the militants also detonated three bombs, the handout said.

Explore: Urdu bazaar: The world of books

One of the militants was killed when he was hit by bullets fired by Rangers personnel while trying to flee, while three other militants blew themselves up, the paramilitary force said.

A list issued by the Karachi police surgeon's office later in the day said three men and a woman were brought dead to the Civil Hospital after the Rangers operation, as well as the body of a baby girl said to be 2-3 months old.

Rangers claimed to have recovered a huge cache of automatic weapons, ammunition and hand grenades from the slain militants.

One of the killed militants was identified as Mohammad Zahid, but the other three militants were mutilated beyond recognition due to the blast.

The building was cleared after a thorough search, Rangers said.

Located on M.A. Jinnah road, Urdu bazaar is one of the oldest book markets in Pakistan. The bazaar is a hub for all services related to printing and publishing, with wholesalers selling paper, stationary and other materials required in the publishing industry.