ISLAMABAD, Pakistan _ Islamic State claimed responsibility Tuesday for an attack on a police academy in southwestern Pakistan that killed at least 60 cadets, demonstrating the militant organization's enduring ability to create havoc far from its shrinking bases in Iraq and Syria.
The extremist group's mouthpiece, the Amaq News Agency, said its South Asia wing � known as Islamic State in Khorasan � carried out a "three-man suicide raid" on the Baluchistan Police College, one of the deadliest terrorist attacks in Pakistan this year.
Police said three militants armed with automatic rifles and grenades attacked the police training center on Monday night in Quetta, the capital of volatile Baluchistan province, taking aim at dormitories where hundreds of cadets ages 15 to 25 are housed.
The death toll by Tuesday morning had surpassed 60. Nearly all the dead were cadets, according to a rescue official who requested anonymity because he was not authorized to speak to the media.
More than 120 people were injured, including cadets who fled the explosions by scaling the compound's 10-foot perimeter wall. Survivors told reporters outside the academy that the assailants' faces were obscured by masks or scarves.
"They were carrying Kalashnikovs and firing indiscriminately on the cadets inside hostels," one said.
There were competing claims of responsibility, as often happens after such attacks, but analysts said the support � if not direct operational involvement � of Islamic State was likely. While Iraqi forces mount a drive to rout Islamic State from its base in the city of Mosul, the militant group's allies have demonstrated their ability to carry out attacks in Afghanistan and Pakistan.
Maj. Gen. Sher Afgan, chief of the paramilitary Frontier Corps in Baluchistan, said the assailants were members of Lashkhar-e-Jhangvi al-Alami, a Sunni Muslim extremist group that has attacked Pakistani security installations and religious minorities, particularly Shiites.
"We have intercepted communications which showed they were in contact with their handlers in Afghanistan," Afgan said.
Analysts say the group's members have links to Islamic State in Khorasan, which is active in neighboring Afghanistan and shares its anti-Shiite ideology. Abu Muhammad Adnani, a senior leader of Islamic State who was reportedly killed in a U.S. drone strike in Syria in August, called on his followers to kill Shiites because they were not true Muslims.
Over the past two weeks, Lashkar-e-Jhangvi al-Alami claimed to have assassinated four Shiite women in Quetta and a Shiite place of worship in the port city of Karachi, while Islamic State in Khorasan said it carried out an attack on a Shiite mosque in the Afghan capital, Kabul, that killed at least 18 people.
"The groups have shared interests in sectarian violence," said Abdul Basit, a fellow at the International Center for Political Violence and Terrorism Research at Singapore's S. Rajaratnam School of International Studies.
Lashkar-e-Jhangvi al-Alami is one of several cells of Lashkar-e-Jhangvi, which the State Department designated a foreign terrorist organization in 2003. The group is blamed for some of the deadliest sectarian attacks in Pakistan's recent history, including a 2013 attack on a pool hall in Quetta that killed nearly 100 people, mostly Shiites.
Pakistani militant factions have split apart and formed new alliances over the past two years as counter-terrorism operations targeted the Pakistani Taliban, a loose federation of extremist outfits seeking to impose Islamic sharia law.
Many fighters went underground or sought refuge in Afghanistan, where intelligence officials say some factions have rebranded themselves as Islamic State.
The patchwork of allegiances often leads to dueling claims of responsibility for attacks. Early Tuesday, hours before Islamic State claimed involvement, the Pakistani Taliban faction said it had carried out the raid at the police academy as "vengeance" for its members who had been killed by security forces.
A day earlier, both the Pakistani Taliban and Islamic State had issued dueling claims of responsibility in the killing of a police intelligence officer in the northwestern city of Peshawar, according to the SITE Intelligence Group, which monitors communications by extremists.
As Islamic State comes under growing pressure in Iraq and Syria, analysts say some of the thousands of fighters it is believed to have attracted from South and Central Asia are beginning to stream back to their home countries.
Other Pakistani militants are able to cross over from Afghanistan to carry out attacks, raising fears of more sectarian attacks after several years of declining violence.
"They lied low for about two years, but now they are returning," Basit said. "And they are not just returning from Afghanistan but also coming back from Iraq as well. Even if half of Islamic State's fighters from South Asia, or one-fourth of them, return to this region, things will get very hot."
Many experts were aghast at Pakistan's failure to protect a sensitive security installation in a province that is of growing importance to China, its biggest ally.
Pakistan's least-developed province, Baluchistan is a key region for Beijing's $46-billion China-Pakistan Economic Corridor, a series of infrastructure projects that aims to link the western Chinese province of Xinjiang to the Arabian Sea via a deep-water port at Gwadar.
China has expressed concerns about security for its construction teams in Baluchistan, where separatist groups seeking to create an ethnic Baluch state have opposed the project.
