Monday’s attack in Shabwa is one of the deadliest reported since the start of the escalation.

Shabwa province’s media office said in a statement that ballistic missiles struck the Martyr Ahmed al-Sulaimani Training Centre, where recruits from several provinces were undergoing training to be members of the internal security forces. According to a preliminary assessment, 53 were killed and more than 200 injured, it added.

A video posted on social media appeared to show several bodies scattered across the ground.

Shabwa’s deputy governor, Fahad al-Khalifi, told AFP news agency that hospitals in the province were overwhelmed and had been forced to transfer the most seriously wounded to neighbouring Hadramout and Aden, where the government is based. Some of them were in a critical condition, he said.

Information Minister Moammar al-Eryani said the attack constituted a war crime because the internal security forces training centre was not a military target.

He also accused the Houthis of “attempting to fabricate a false media victory, boost the morale of its collapsing elements, and cover up the defeats and setbacks it is suffering across various combat axes”.

The Houthis’ military spokesman, Yahya Sarea, said in a statement that the missiles targeted a gathering of “Saudi enemy” forces at al-Alam camp, which he said was run by Saudi officers.

There was no immediate comment from Saudi authorities.

In a separate development, Houthi-run media reported that a Saudi air strike on a home in the Sahar district of the Houthi-controlled northern province of Saada on Sunday killed at least 10 people and injured 23 others, many of them women and children.

According to the Houthi-run health ministry in north-western Yemen, a total of 141 people had been killed in Saudi strikes over the past seven weeks.

The government’s health ministry, meanwhile, said last week that at least 1,282 people had been killed in the conflict across Yemen since 6 August.

In Saudi Arabia, at least 19 people have been killed in Houthi attacks targeting the kingdom’s airports since the beginning of October.

Yemen has been devastated by a civil war that began in 2014, when the Houthis ousted the government from the capital, Sanaa. The conflict escalated in 2015, after the Saudi-led coalition intervened in an attempt to restore the government’s rule.

A four-year-old informal ceasefire began to unravel in July, when the Houthis announced a “maritime embargo” against Saudi Arabia and began missile and drone attacks on Saudi airports, oil facilities and tankers in the Red Sea.

The Houthis said they were retaliating for what they call a Saudi blockade of their territory, as well as an air strike on Sanaa airport that they blamed on the kingdom.