At least 59 people including security personnel have been killed in the standoff, according to health officials cited by Reuters.
Pakistani military commandos have managed to rescue over 200 hostages, according to local media reports.
CNN reports that Major-General Sher Afgan, Chief of the Paramilitary Frontier Corps, told reporters Tuesday that Pakistan-based group Lashkar-e-Jhangvi was behind the attack — an al Qaeda-linked militant group that has repeatedly carried out deadly attacks on the country's Shiite Muslim minority in recent years.
One attacker was reportedly killed by security forces; two others died when they detonated bombs they were carrying, said Sarfraz Bugti, Home Minister for Balochistan province, where Quetta is located. He added the assault ended in the early hours of Tuesday.
The attackers targeted a hostel at the academy where as many as 700 police cadets live. Two hundred cadets were rescued Monday night, Bugti said.
Five or six “terrorists entered the training school and (went) straight to the hostel where they took cadets hostage,” the Pakistani army said in a statement.
Lashkar-e-Jhangvi is known for targeting Shiites in Sunni-majority Pakistan, including a series of bombings in early 2013 that left more than 160 people dead in Balochistan province.
Last year, the then head of the group, Malik Ishaq, was killed during a shootout after armed men on motorcycles ambushed a police convoy that was transporting him between prisons in Punjab province.
Lashkar-e Jhangvi also claimed responsibility for a January 2014 bombing of a bus carrying Shiite pilgrims that killed more than 20 people.
The group was outlawed in Pakistan in 2001 and designated a terrorist organization by the US State Department in 2003.
