Two suicide car bombers have rammed their vehicles into a Shiite rebels’ checkpoint and a house south of the Yemeni capital as a school bus was travelling nearby, killing at least 25 people including at least 15 primary school pupils, according to the Yemeni government, rebels and witnesses.

Witnesses said that the first car was loaded with potatoes apparently disguising explosives underneath.

When the car bomber arrived at the checkpoint manned by rebels, he blew up the vehicle as the school bus was passing.

After the first explosion, a second car targeted the home of a Shiite rebel leader, Abdullah Idris.

The Defence Ministry said in a statement that at least 25 people were killed in the twin bombings, however the Interior Ministry later said three children were killed and 37 wounded with eight in critical condition. It was impossible to independently confirm the casualty figures.

Witnesses at the site of the attack said that the rebels brought four pick-up trucks and dumped dozens of bodies into them while several ambulances rushed to the scene to carry away the wounded. Body parts littered the street along with open bags of potatoes.

The Shiite rebels, known as the Houthis, blamed al-Qaida for the attack in the Radaa area of Baydah province, calling it “the ugliest crime against childhood”. The group said the school bus was carrying female primary school pupils.