Pakistan attack
A Pakistani soldier stands guard outside the Police Training Center after an attack on the center in Quetta, Pakistan October 25, 2016.Reuters

At least 60 people were killed and more than 100 were injured in a militant attack on a police academy near Quetta, Pakistan, on Monday night.

A military counter-operation to defeat the militants continued overnight and the officials on Tuesday morning said that the operation was successful. Militants attacked the Balochistan Police College, located 20 km east of Quetta, at 11.00 pm on Monday. The compound had around 700 recruits at the time of the attack, however, hundreds of people were rescued in the operation, according to reports.

ISIS on Tuesday claimed responsibility for the gruesome attack. The militant group's Amaq news agency stated that the attack was carried out by "Islamic State fighters."

Pakistan Prime Minister Nawaz Sharif postponed all engagements in Islamabad and arrived in Quetta on Tuesday morning. The PM is scheduled to chair a high-level meeting in the city to discuss the law and order situation. sharif is also expected to visit the injured cadets in the hospital.

Three militants, armed with guns and suicide jackets, attacked the academy compound, Balochistan province home minister Sarfaraz Bugti said. There were earlier reports of there being at least five to six assailants in the compound.

"They first targeted the watch tower sentry, and after exchanging fire killed him and were able to enter the academy grounds," the minister said.

"I saw three men in camouflage whose faces were hidden carrying Kalashnikovs. They started firing and entered the dormitory but I managed to escape over a wall," a police cadet was quoted as saying by AFP.

The chief of the paramilitary Frontier Corps in Balochistan Major General Sher Afgan said that the "the attack was over in around three hours after we arrived." The paramilitary Frontier Corps led the counter-attack against the militants in the compound.

Afgan also said that the militants belonged to the Al-Alimi faction of the Lashkar-e-Jhangvi militant group, which is affiliated with the Pakistani Taliban. He said that according to the communications intercepts, it was found that the militants were in touch with operatives in Afghanistan.

Chief of Army Staff (COAS) Gen Raheel Sharif reached Quetta on Tuesday , Inter-Services Public Relations (ISPR) said. The army chief is expected to visit a hospital to see the cadets injured in the attack.

The United States condemned the attack on the Quetta Police Training Centre. The US Spokesperson for the Department of State, John Kirby, on Tuesday addressed a press briefing and expressed sympathy for the slain and injured cadets in the attack.

"In this difficult hour, we are with the people and government of Pakistan," Kirby said. Kirby also added that the United States was working with Pakistan to battle terrorism in the region.

No militant group has claimed the responsibility for the attack yet.