This article is more than 1 year old

This article is more than 1 year old

More than 100 people are believed to have been killed in an airstrike by the Saudi-led military coalition on a detention centre in Yemen, according to the International Committee of the Red Cross (ICRC).

The coalition said it had targeted a facility run by Houthi rebels that “stores drones and missiles”, but the rebels said the attack had levelled a building they used as a prison.

The ICRC rushed to the scene in the city of Dhamar with medical teams and hundreds of body bags.

“The location that was hit has been visited by ICRC before,” said Franz Rauchenstein, the committee’s head of delegation for Yemen. “It’s a college building that has been empty and has been used as a detention facility for a while. What is most disturbing is that [the attack was] on a prison. To hit such a building is shocking and saddening – prisoners are protected by international law.”

Rauchenstein said more than 100 people were estimated to be dead and at least 40 survivors were being treated for their injuries in hospitals in the city, south of the capital, Sana’a.

Quick guide The Yemen conflict explained Show Hide How long has the war been going on? Yemen has been troubled by civil wars for decades, but the current conflict intensified in March 2015 when a Saudi-led coalition intervened on behalf of the internationally recognised government against Houthi rebels aligned with the former president Ali Abdullah Saleh. The war is widely regarded as having turned a poor country into a humanitarian catastrophe. Riyadh expected its air power, backed by regional coalition including the United Arab Emirates, could defeat the Houthi insurgency in a matter of months but instead it has triggered the world's worst humanitarian disaster, with 80% of the population - more than 24 million people - requiring assistance or protection and more than 90,000 dead.

What is the cause of the war? Its roots lie in the Arab spring. Pro-democracy protesters took to the streets in a bid to force the president, Ali Abdullah Saleh, to end his 33-year rule. He responded with economic concessions but refused to resign. By March 2011, tensions on the streets of the capital city, Sana’a, resulted in protesters dying at the hands of the military. Following an internationally brokered deal, there was a transfer of power in November to the vice-president, Abd Rabbu Mansour Hadi, paving the way for elections in February 2012 – in which he was the only candidate to lead a transitional government. Hadi’s attempts at constitutional and budget reforms were rejected by Houthi rebels from the north. The Houthis captured the capital, forcing Hadi to flee eventually to Riyadh. Photograph: Mohamed Al-Sayaghi/X03689

ICRC teams collecting bodies were “working relentlessly to find survivors under the rubble”, he said, but cautioned that the chances of finding any were very slim.

Footage obtained by AFP showed heavy damage to the building and several bodies lying in the rubble, as bulldozers worked to clear away huge piles of debris.

The coalition intervened in 2015 to support the government after the Iran-aligned Houthis swept out of their northern stronghold to seize Sana’a and much of Yemen, one of the Arab world’s poorest nations.

Fighting since then has claimed tens of thousands of lives and sparked what the UN calls the world’s worst humanitarian crisis.

Both sides stand accused of actions that could amount to war crimes. The coalition has been blacklisted by the UN for the killing of children, while Saudi Arabia and its allies accuse the Houthis of using civilians as human shields in densely populated areas.

Before the ICRC’s comments, the coalition had insisted the strike was conducted against “a military compound which was a legitimate military target”.

It said secondary explosions indicated the building was used to store weapons and that the Houthis were masking its identity by “claiming it was a secret prison”.

“This is a traditional Houthi tactic and a violation of the laws of armed conflict. This site was not registered with the United Nations [and] was not on the no-strike list,” said a coalition spokesman, Col Turki Al-Malk.

The coalition earlier said that it “took all precautionary measures to protect civilians”, but the Houthi television channel Almasirah said dozens of people had been killed and wounded in seven airstrikes that hit the building.