ISIS has claimed responsibility via its Amaq media wing for a deadly attack Monday night on a police academy in Quetta, Pakistan.
The claim conflicts with an earlier statement from Pakistani officials Tuesday, in which authorities said the al Qaeda-linked militant group Lashkar-e-Jhangvi was behind the attack. Lashkar-e-Jhangvi has not issued a claim of responsibility.
ISIS had previously claimed responsibility for a deadly terror attack in the city which was also claimed by Jamaat-ul-Ahrar, a splinter group of Pakistan's Tehreek-i Taliban (TTP).
Cadets at a police training academy in Pakistan awoke to the horror of suicide bomb-wielding terrorists in an attack late Monday that killed 61 and injured 117.
"We were sleeping when terrorists attacked the center," said Asif Hussain, a cadet who was in the academy's barracks at the time.
He said cadets had no guns and were powerless to fight back when the militants struck through the window.
Three attackers were killed during the assault targeting a hostel at the academy, said Sarfraz Bugti, home minister for the southwestern Pakistani province of Balochistan.
Security forces killed one, and two others died when they detonated the bombs they were carrying, he said.
At least 260 cadets were rescued during the assault, which lasted through early Tuesday, he said.
Maj. Gen. Sher Afgan, chief of the paramilitary Frontier Corps, told reporters Tuesday that Pakistan-based group Lashkar-e-Jhangvi was behind the attack. The al Qaeda-linked militant group has repeatedly carried out deadly attacks on the country's Shiite Muslim minority in recent years.
Three days of mourning have been announced in Balochistan province for the dozens of dead, most of whom were police cadets.
Safar Khan, a 24-year-old cadet who was inside his barracks when gunshots rang out, told CNN the survivors refused to be intimidated.
"We will not bow down before terrorists," he said.
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 group's leader, Malik Ishaq, was killed during a shootout after armed men on motorcycles ambushed a police convoy transporting him between prisons in Punjab province.
Laskhar-e Jhangvi also claimed responsibility for a January 2014 bombing of a bus carrying Shiite pilgrims that killed more than 20 people.
Pakistan outlawed the group in 2001, and the US State Department designated it as a terrorist organization two years later.
Balochistan has long been plagued by violence.
In August, its capital, Quetta, was the scene of one of Pakistan's deadliest attacks when gunmen killed prominent lawyer Bilal Kasi, president of the Balochistan Bar Association.
Hours later, more than 72 people died in a bombing at a hospital where his body was taken.
"No one will be allowed to disturb peace in the province that has been restored due to countless sacrifices of security forces, police and the people of Balochistan," Pakistani Prime Minister Muhammad Nawaz Sharif said at the time.
Sharif said he had directed authorities to "maintain utmost vigilance."