At least 87 people were killed and 266 injured, some critically, in a Saudi airstrike on a prison in Yemen's rebel-held north, Public Health and Population Minister Taha al-Mutawakil said on Saturday.

The Houthi rebel group claimed on Friday that the Saudi-led coalition had launched a raid on territory that it controls in the northern city of Saada.

The attack, which coincided with a coalition strike on the port of Hodeida that killed three children and knocked out the impoverished country's internet, was condemned by UN Secretary General Antonio Guterres.