ISLAMABAD, Oct. 25 (Xinhua) -- Gunmen stormed a Pakistani police training academy in the southwestern city of Quetta late Monday night, leaving at least 59 dead and more than 100 wounded, officials said Tuesday, after declaring the finish of a counter-operation.

The terrorist attack on the Balochistan Police College, located 20 km east of Balochistan Province's capital Quetta, began at around 11:05 p.m. (1805 GMT) Monday.

Around 500 to 700 police personnel including trainees and instructors were stationed at the academy, and some 200 had been taken hostage, officials said.

Interior Minister of the Balochistan Province Mir Sarfaraz Ahmed Bugti said at the site early Tuesday that three terrorists involved in the attack were killed by security forces during the four-hour operation against them. Earlier, the minister said four terrorists had been killed during the operation.

"One of the terrorists was killed by the security personnel, while two others exploded their jackets near the captives after they were cordoned off by the army commandos, which caused sharp rise in death toll," said Bugti.

Major-General Sher Afgun, chief of the paramilitary force Frontier Corps, said the operation against the terrorists was concluded, and a search and clearance operation has started in the premises of the police training center.

According to Afgun, a group of three terrorists armed with suicide vests, automatic guns and hand grenades sneaked into the center from the backyard after killing a guard at a watchtower at night.

The terrorists occupied a hostel of the police training center and made around 200 policemen hostage in the dining hall of the hostel located at the Saryab Road area of Quetta.

Following the attack, personnel of Pakistani army and Frontier Corps reached the site and cordoned off the training center and launched the operation.

Exchanges of intense firing were heard after the contingents of army and Frontier Corps entered the training center and started the operation to neutralize the terrorists.

District Coordination Officer of Quetta Abdul Wahid Kakar also confirmed that 109 injured people were transferred from the training center to different hospitals of the city.

An eyewitness police trainee said, "We were sleeping in our room when we heard firing, we rushed out, I saw two terrorists were firing at another room, I ran to the roof of the hostel and from there I managed to come out."

Authorities have declared a state of emergency in all hospitals in Quetta and appealed to the public for blood donations.

Pakistani Prime Minister Nawaz Sharif condemned the attack and said terrorists cannot demoralize the nation with such a coward attack and that the country's ongoing war on terror will be taken to a logical end.

No group has claimed responsibility for the attack yet. However, Afgun said the terrorists belonged to a banned outfit Lashkar-e-Jhangvi al-Almi and they were taking instructions from their handlers based somewhere in Afghanistan.