Explosions have been heard near a military academy in Afghanistan's Kabul on Monday morning, BBC reported.
Witnesses said they heard several explosions and gunfire at around 05:00 (00:30 GMT) at the academy on the outskirts of Kabul where high-ranking military officers are trained. Monday's attack comes two days after a massive Taliban-claimed suicide auto bombing in the city that killed over 100 people and left more than 230 people injured.
According to Reuters, police said there had been an incident inside at a military site but said it was not clear if it was an attack by militants.
According to the Tolo News, the number of attackers is still unknown, while the Afghan security forces have cordoned off the area as the attack is ongoing.
Additionally, one attacker has been arrested and another is still fighting with security forces.
In October, a Taleban suicide bomber killed 15 Afghan army trainees as they travelled home from the Marshal Fahim academy.
Afghan military institutions are frequently targeted by militants.
Saturday's blast in one of the most heavily protected parts of the city, close to foreign embassies and government buildings, was the worst seen in the Afghan capital since a truck bomb near the German embassy killed 150 people in May. There are so far no official reports of fatalities or injuries.
Islamic State fighters attacked Save the Children's office in Afghanistan's east on Wednesday that officials said killed five people and wounded another 26.