The Dawood Khan Military Hospital -- commonly known as the 400-Bed Hospital -- is in Kabul’s diplomatic enclave and close to the U.S. embassy and NATO headquarters.
A gun battle between an unknown number of militants and security forces was ongoing.
According to police, a suicide attacker detonated explosives at the hospital entrance before “a number” of attackers armed with assault rifles and grenades storm the building and made their way to the second and third floors.
“At this moment, I can only confirm that it is a complex attack involving a number of militants,” Interior Ministry spokesman Sediq Seddiqui told Anadolu Agency.
“The Afghan National Police’s Special Forces have engaged them and soon they will be eliminated.”
He said there were no confirmed casualties.
The NATO-led Resolute Support Mission has offered to assist the National Police in the operation to clear the hospital.
No group claimed immediate responsibility for the attack, which came days after the Taliban attacked three security installations in Kabul, killing 22 people.