Afghanistan’s Defense Ministry says a suicide bomber killed at least 15 Afghan cadets as they were leaving a military training center in Kabul, late in the afternoon of October 21.

Four others were wounded in the powerful blast at the gates of the Marshal Fahim National Defense University, said Dawlat Waziri, a ministry spokesman.

The attacker was on foot when he struck the minibus carrying the cadets, who were on their way home, Waziri added.

The Taliban militant group claimed responsibility for the attack.

The office of President Ashraf Ghani said in a statement that the targeting of security forces illustrated the militants' "isolation."

The latest suicide bombing brings the death toll of a week of attacks by various militant groups across the conflict-torn country to 200.

It’s the fifth attack targeting Afghan security forces this week.

In the deadliest of the recent attacks, at least 43 Afghan soldiers were killed in a Taliban-claimed assault on a military base in the southern province of Kandahar on October 19.

On October 17, Taliban suicide bombers and gunmen stormed a police training center in the southeastern city of Gardez, killing 41 people.

On the same day, 31 people, including police officers and civilians, were also reported killed and 10 others wounded in an attack blamed on the Taliban in the neighboring province of Ghazni. Two police officers were killed in another militant attack in Ghazni.

The assault on the cadets in Kabul comes a day after about 90 worshipers were killed and dozens more wounded in two separate attacks on mosques in the capital, Kabul, and the western province of Ghor on October 20.

The Islamic State (IS) extremist group claimed responsibility for the suicide bomb and gun attack on the Shi’ite mosque in Kabul. IS didn’t provide evidence for its claim, but it has attacked Shi'ite mosques before. An Interior Ministry spokesman said that 56 people were killed and at least 55 others were wounded in that attack.

It is not clear who carried out the attack on the Sunni mosque in Ghor that killed at least 33 people and wounded 10 others according to Afghan officials.

With reporting by AP, AFP, dpa, Reuters, and he BBC