At least 35 people have died and hundreds more have been wounded in separate bomb attacks over the last 24 hours in the Afghan capital Kabul.
A suicide bomber blew himself up near the city's police academy on Friday evening, killing about 20 recruits.
A short while later a large explosion was heard north of the airport.
In the early hours of Friday, a truck carrying explosives was detonated near an army base in the Shah Shahid area, claiming 15 lives.
The Taliban has claimed only one attack - the suicide bombing of the police academy.
President Ashraf Ghani has suggested that the group is seeking to divert attention away from its leadership struggles.
Officials said Friday evening's suicide bomber was dressed in police uniform when he detonated an explosives-laden vest outside the gates of Kabul's police academy.
He had stood among a queue of police cadets who were waiting to enter the building having returned from their two-day weekend, officials said.
At least 25 cadets were wounded.
"It was huge, all the victims are military students," said one local resident. "They were all students of the academy."
Observers say the attack on the police academy marks a serious breach of security in an already heavily-fortified city.
Just two hours after this attack, a loud explosion was heard across much of the city followed by sustained gunfire, the BBC's Philip Palmer reports from the Afghan capital.
Police said the attack was to the north of the airport, close to an area housing several Nato and Afghan military bases and training facilities.