Explosions targeting educational institutions killed at least six people, including students, and injured 17 Tuesday in a mostly Shia neighbourhood of Kabul, the police said.

The blasts, which occurred in rapid succession, were being investigated and more casualties were feared, according to Kabul police spokesman Khalid Zadran and the city’s Emergency Hospital. Several of the wounded were in serious condition and some had been treated and released.

The explosions occurred inside the Abdul Rahim Shaheed High School and near the Mumtaz Education Centre several kilometres away, both in the predominately Shia Muslim neighbourhood of Dasht-e-Barchi. 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.

The AP spoke to several private guards in the area but they refused to give their names, fearing repercussions from the Taliban security force cordoning off the area.

It appeared a suicide bomber blew himself up inside the sprawling compound, which can house up to 1,000 students, witnesses said. It wasn’t immediately clear how many children were in the school at the time of the explosion.

The school is teaching students 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 immediately claimed responsibility.