Several dead after suicide blast hits Kabul police academy

A suicide bomber dressed in a police uniform struck outside the gates of a police academy in Kabul on Friday evening, killing at least 20 recruits and wounding 25, Afghan officials said, less than a day after a huge truck bomb detonated in the Afghan capital, killing 15 and wounding hundreds.

A police source said the bomber struck as cadets were returning to the academy after the weekend. The bomber was dressed in a police uniform and blew himself up when he could not get into the academy, Al Jazeera's Jennifer Glasse reported. 

One police officer, who spoke on condition of anonymity because he was not authorized to talk to reporters, told the Associated Press there were at least 25 wounded among the recruits. Reuters estimated the number of people killed or wounded at 60. 

The Taliban claimed responsibility for the attack, which comes as the group steps up its summer offensive despite a bitter power struggle in its ranks. 

The uptick in attacks highlights growing insecurity in the country amid a faltering peace process with the Taliban as Afghan forces face their first summer fighting season without full NATO support.

A U.N. report published Wednesday said civilian casualties in Afghanistan hit a record high in the first half of 2015.

The report said 1,592 civilians were killed, a 6 percent drop from last year, but the number of injured jumped 4 percent, to 3,329.

Overall, casualties reached their highest level since the U.N. began issuing its authoritative reports in 2009. The statistics are a grim indicator of the expanding insurgency, with Afghan forces increasingly battling the fighters on their own after NATO's combat mission ended in December.

Al Jazeera and wire services