Pakistan attack: Vigils held for Bacha Khan University dead
Vigils have been held in Peshawar and elsewhere in Pakistan for at least 21 people killed in a university attack.
Four suspected attackers also died in Wednesday's assault on Bacha Khan University in Charsadda.
Military spokesman Lt Gen Asim Bajwa told reporters that major breakthroughs had been made in identifying the attackers but did not name them.
One Pakistani Taliban commander said the group carried out the assault, but its main spokesman denied this.
The group killed 130 students at a school in Peshawar in 2014.
Early on Wednesday, gunmen entered Bacha Khan University in Charsadda, 50km (30 miles) from Peshawar, and opened fire on students and faculty as they gathered for a poetry event.
Those killed were a professor, two gardeners, one caretaker and 17 students, according to Pir Shahab, superintendent of investigations, who spoke to AFP news agency. Most of the victims were shot dead at a hostel for male students.
The death toll rose to 21 after two of the injured died in hospital, police said on Thursday. Officials say seven other survivors are in a stable condition, AFP reports.
The attack sparked widespread outrage in the country and candlelight vigils were held for the victims in the south-western city of Quetta. Dozens of people protested in Karachi.
Authorities say they have gathered information from the mobile phones of the attackers about where they came from and who sent them.
"The terrorists were continuously conversing on their mobile phones, two of which we have recovered," Lt Gen Bajwa said.
But he said the information was "sensitive" and would be shared with the public later, according to Dawn newspaper.
BBC Urdu's Asad Ali Chaudry says there is a symbolic value attached to Bacha Khan University, as it is named after a Pashtun nationalist leader who believed in non-violent struggle.
The title of Wednesday's poetry programme in his honour was "peace", he adds.
Just days ago, some schools in Peshawar were closed by the authorities amid reports that militants were planning an attack.
Deadly recent attacks in Pakistan
- 20 January 2016: Militants kill at least 19 people in attack on Bacha Khan University in Charsadda, near Peshawar
- 13 December 2015: Bomb blast kills 24 people at a clothes market in the Kurram tribal region
- 18 September 2015: Taliban militants kill 29 people in an attack on an air force base in Peshawar
- 13 May 2015: Gun attack on a bus carrying Ismaili Shia Muslims in Karachi leaves at least 45 people dead
- 13 February 2015: Militants attack a Shia mosque in Peshawar with guns and grenades; at least 20 people killed
- 30 January 2015: Bomb blast at a Shia Mosque in Shikarpur district, Sindh province, kills at least 40 people