DUSHANBE, January 21, 2016, Asia-Plus -- On Wednesday, a little more than a year after Pakistani Taliban insurgents killed about 150 students and teachers at a school in northwestern Pakistan, militants took new aim at students on track to make up the country’s future professional class, The Washington Post reported.

The attack at Bacha Khan University, which was claimed by a splinter group of the Pakistani Taliban, began shortly after 9 am.

The gunmen shot and killed 20 students and two teachers, some execution-style, and wounded nearly two dozen others.

According to the newspaper, several students said the toll could have been much higher were it not for a teacher armed with a pistol who briefly held off the attackers before being killed.

The guards battled the attackers before police and paramilitary forces arrived, which kept the gunmen from entering the women’s dormitory, the Washington Post reported citing Pakistani officials.  

Maj. Gen. Asim Bajwa, a spokesman for the Pakistani military, said investigators are trying to determine the nationalities of the gunmen and who supplied them with weapons.

A Pakistani Taliban regional group — led by Omar Mansour from the Darra Adamkhel region — sent a statement to reporters Wednesday claiming responsibility. Mansour is also believed to have been a mastermind behind the Peshawar school attack.

But highlighting an emerging split within the group, the main Pakistani Taliban faction issued a separate statement denouncing the killings as “un-Islamic.”

Pakistan’s military says that in the past year it has largely driven groups such as the Taliban and al-Qaeda from the country’s northwestern tribal belt, which became a hub of domestic and international terrorist groups after the 9/11 attacks.  But security officials and analysts have warned for months that Pakistan remains vulnerable to major attacks because government leaders have not mounted a widespread offensive against the roots of militancy, including conservative religious seminaries.

The attack is also refocusing attention on the vulnerabilities of schools, both in Pakistan and the West.