Fifty-three people were killed and 200 others injured in a Houthi attack on a government security forces training camp in Yemen’s Shabwa province on Monday, according to local authorities, as fighting intensifies in the war-torn country.

Video verified by Reuters from Shabwa showed injured people and bloodied bodies scattered across the ground.

Local authority sources, speaking on condition of anonymity, said the Houthis had fired three ballistic missiles at security forces during a training exercise. Shabwa is an energy-rich province in south-central coastal Yemen.

The Iran-aligned Houthis and Yemen’s internationally recognised government, backed by a Saudi-led coalition, have been exchanging attacks since the group advanced in September towards territory near the Bab el-Mandeb Strait, a strategic shipping chokepoint at the entrance to the Red Sea.

Government forces began a campaign this month to recapture Houthi-controlled areas, regaining ground near the strait. Meanwhile, the Houthis have laid siege to Taiz, the last major urban stronghold of anti-Houthi forces in Yemen’s southern highlands.

The conflict has become another front in the wider US-Israeli war on Iran, as the Houthis have stepped up attacks on Saudi Arabia, the world’s largest crude oil exporter. Their targets have included Riyadh’s international airport and state oil giant Saudi Aramco.

Yemen’s war began in 2014 when the Houthis seized the capital, Sanaa, forcing the government to retreat south. A Saudi-led military intervention followed in 2015, leading to years of fighting and a bloody stalemate. The two sides agreed to a truce in 2022, which held until this year.

Yemen is already facing one of the world’s worst humanitarian crises, with aid agencies warning that conditions are deteriorating rapidly.