Two assailants were killed in the attack on a security training center in the 5th Police District of Kabul, Kabul police spokesman Hashmat Stanikzai said.

Militants stormed a security training center in Qala-e-Wazir locality in the 5th Police District, Kabul city at 10:00 a.m. local time Thursday, triggering a gun battle which lasted for more than six hours.

According to Stanikzai, the attackers were two persons and both had been killed. Without commenting on the possible casualties of security personnel, the official said the situation had been brought under control.

Meantime, a police personnel at the site who declined to be named said the attackers occupied an under-construction building in 5th Police District this morning and targeted a training center of the National Directorate for Security (NDS) or the country's intelligence agency.

No group has claimed responsibility for the attack.

This is the second shocking attack in Kabul city over the past two days.

On Wednesday, a suicide bomber blew himself up in a school training center in the 18 Police District, killing 34 students and injuring 56 others. The hardliner Islamic State group has claimed the attack.