Explosions targeting educational institutions have killed at least six people, including pupils, and injured 17 in a mostly Shiite neighbourhood of Afghanistan’s capital, police said.

More casualties are feared after the blasts, which occurred in rapid succession, according to Kabul police spokesman Khalid Zadran and the city’s Emergency Hospital.

Several of the wounded are in critical condition.

The explosions occurred in Abdul Rahim Shaheed High School and near Mumtaz Education Centre, both in the Dasht-e-Barchi neighbourhood.

There were no immediate reports of casualties at the Mumtaz Centre.

Guards in the narrow street leading to the two-storey high school said they saw 10 casualties.

Inside the school, an Associated Press video journalist saw walls splattered with blood, burned notebooks and children’s shoes.

It appeared a suicide bomber blew himself up inside the sprawling compound, which can house up to 1,000 pupils, witnesses said.

It was not immediately clear how many children were in the school at the time of the explosion.

The school teaches pupils only until the sixth grade after Afghanistan’s hardline Taliban rulers went back on a promise to allow all girls to attend school.

No one has claimed responsibility for the explosions.

The area has been targeted in the past by Afghanistan’s Islamic State affiliate, which reviles Shiite Muslims as heretics.

Save the Children in Afghanistan issued a statement “strongly condemning ” the attack and saying “no school should be deliberately targeted, and no child should fear physical harm at or on the way to school”.

The UN’s high commissioner for refugees, Filippo Grandi, said he joined the world body’s special representative for Afghanistan, Deborah Lyons, in offering condolences to families of the victims. He said the attack against the school was “horrific and cowardly”.

The Islamic State affiliate known as IS in Khorasan Province, or IS-K, has previously targeted schools particularly in the Shiite dominated Dasht-e-Barchi neighbourhood.

In May last year, months before the Taliban took power in Kabul, more than 60 children, mostly girls, were killed when two bombs were detonated outside their school in Dasht-e-Barchi.

IS has presented the biggest security challenge to the country’s Taliban rulers, who swept into Kabul last August as the US ended its 20-year war.