SANAA, Yemen -- The death toll in an airstrike by the Saudi-led coalition on a prison complex in western Yemen has risen to 58, security officials said on Sunday.

Abdel-Rahman al-Mansab, a security chief of the district of al-Zaydia in the Red Sea port of Hodeida, said most of the dead in Saturday's airstrike were prisoners. They were among a total of 115 inmates who were serving jail terms for misdemeanour crimes or who were still in pretrial detention.

The city is under control of Yemen's Shiite Houthi rebels, who seized the capital and much of the northern region in 2014. The Houthi takeover has forced the internationally-recognized government to flee the country and request military intervention by neighbouring Gulf states, which have carried an extensive air campaign in Yemen since March last year.

The conflict has left more than 10,000 dead and injured and displaced nearly three million Yemenis while pushing the Arab world's poorest nation to the brink of famine.

Rights groups have accused the coalition of systematically carrying attacks on civilians.

On Sunday, the Saudi-led coalition said the prison complex is used as a command centre for Houthis.

Al-Mansab denied that, saying it is a "civilian" site and added that the complex came under three airstrikes that killed the inmates along with rescuers who came to help the injured. He said there were still bodies under the rubble.

Yemeni officials said at least 20 of the victims were anti-Houthi political detainees who were rounded up over suspicions of co-operating with the coalition.

Al-Mansab also said that the complex has two prisons, one for women and one for men, but there were no female inmates at the time of the attack. "When I went there, I saw a pile up of charred bodies beyond recognition. They were burned to death," he said.

A medical official said that nearly 60 other bodies were transferred to the military hospital in the city, suggesting that some of the victims were security personnel. The official spoke on condition of anonymity because they weren't authorized to speak to the press.

Hodeida is one of Yemen's most impoverished cities. The Saudi-led coalition has repeatedly targeted its port, under the pretext that it is being used by Houthis to smuggle weapons.

The port serves the northern region, including the Houthi-controlled capital. The bombing of the port and a naval and air blockade imposed by the coalition have contributed to the increasing rate of food insecurity in Yemen, which imports 90 per cent of its food.