At least six people have died and several others injured after explosions were heard near a school in Kabul.

Police said the blasts had targeted educational facilities in a mostly Shiite neighbourhood of the Afghan capital city.

There are fears that the number of casualties will rise, as several of those wounded were left in serious condition.

Kabul police spokesman Khalid Zadran said the blasts occurred in rapid succession and were being investigated.

The explosions reportedly occurred inside the Abdul Rahim Shaheed High School and near the Mumtaz Education Centre several kilometres away. It wasn’t immediately clear how many children were in the school at the time. Two Kabul hospitals said they had received 24 people injured in the blasts.

Witness told the Associated Press that a suicide bomber blew himself up inside the school’s grounds. No one has immediately claimed responsibility for the incident.

The area has previously been targeted by affiliates of the so-called Islamic State (IS) group.

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

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 school in question is teaching students only until the sixth grade after Taliban rulers reversed on a promise to allow all girls to attend school.