KABUL: A suicide bomber killed 15 Afghan army trainees as they were leaving their base in Kabul on Saturday, the defence ministry said, in the latest deadly attack in the capital.

"This afternoon when a minibus carrying army cadets was coming out of the military academy, a suicide bomber on foot targeted them, martyring 15 and wounding four," defence ministry spokesman Dawlat Waziri told AFP.

It was the second suicide attack in the Afghan capital in 24 hours and the seventh major assault in Afghanistan since Tuesday, taking the total death toll to more than 200, with hundreds more wounded.

The spate of deadly attacks underscores deteriorating security across the war-torn country.

It was also the fifth time since Tuesday that militants have launched a major attack against Afghanistan´s beleaguered security forces already badly demoralised by high casualties and desertions.