A Pakistani soldier stands guard outside the Police Training Center after an attack on the center in Quetta, Pakistan October 25, 2016. [Photo/Agencies]

At least 59 people were killed and 117 critically wounded when gunman stormed a Pakistani police training academy in the southwestern city of Quetta, government officials said on Tuesday.

Some 200 trainees were stationed at the facility when the attack occurred late on Monday, officials said, and some were taken hostage during the attack which lasted five hours.

Most of the dead were police cadets.

Mir Sarfaraz Bugti, home minister of Baluchistan province, of which Quetta is the capital, had confirmed early on Tuesday that five to six gunmen had attacked a dormitory inside the training facility while cadets rested and slept.

No group immediately claimed responsibility for the attack, but one of the top military commanders in Baluchistan, General Sher Afgun, told media that calls intercepted between the attackers and their handlers suggested they were from the sectarian militant group, Lashkar-e-Jhangvi.

Lashkar-e-Jhangvi, whose roots are in the heartland Punjab province, has a history of carrying out sectarian attacks in Baluchistan, particularly against the minority Hazara Shias. It was unclear what motive the group would have in attacking the police academy, a home ministry official said.

Police, military and paramilitary personnel arrived at the training centre within 20 minutes of the attack and launched an operation which last around five hours, the home ministry said.

Exchange of intense firing has been heard since the contingents of army and Frontier Corps entered the training center and started the operation to neutralize the terrorists, who have held 200-250 police personnel hostage in a hostel of the training center, said Bugti.

Terrorists are also hurdling hand grenades at the armored vehicles of the security forces, local media said.