Image copyright Nasir Behzad, BBC Afghan Service Image caption Saturday's suicide bomb came as Afghans were grieving multiple deaths in two attacks on mosques

At least 15 military cadets have been killed in a suicide attack in Kabul, Afghan officials say, bringing the death toll of a week of attacks by various militant groups to around 200.

Defence ministry spokesman Dawlat Waziri said four others were wounded in the explosion at the gates of Marshal Fahim military academy, as they were leaving by minibus.

The bomber was on foot.

The Taliban have said they carried out the attack.

It was the second suicide attack in the city in 24 hours.

On Friday, 56 people were killed in a gun and suicide bomb attack at a Shia Muslim mosque, claimed by the Islamic State group.

The Sunni Muslim group did not provide evidence for its claim but it has attacked Shia mosques before.

Separately on Friday, 20 people were killed in an attack on a Sunni Muslim mosque in Ghor province. It is not clear who carried out that attack.

Image copyright Nasir Behzad, BBC Afghan Service Image caption About 200 people have died in attacks in Afghanistan in the last week alone

Afghanistan has seen a spate of suicide attacks and bombings in recent months. The country's army and police have suffered heavy casualties at the hands of the Taliban, a Sunni group who want to re-impose their strict version of Islamic law in the country.

The BBC's South Asia editor Ethirajan Anbarasan says attacks from the Taliban and other groups seem to have intensified since US President Donald Trump announced his new Afghan strategy.

After Mr Trump committed US troops to the country, the Taliban said they would turn Afghanistan into a "graveyard" for American soldiers.

In other attacks this week:

On Thursday, 43 Afghan soldiers were killed after two Taliban suicide bombers in Humvee armoured vehicles destroyed a military base in the southern province of Kandahar. Two police officers were also killed in in Ghazni province

On Tuesday, Taliban suicide bombers and gunmen killed at least 41 people when they stormed a police training centre in the eastern city of Gardez

Also on Tuesday, at least 30 people died in car bombings in Ghazni.

In May, a truck bomb in Kabul killed more than 150 people and wounded some 400 more, most of them civilians. No group claimed to be behind that attack but the US-backed Afghan government accused the Haqqani group, an affiliate of the Taliban.