Russia has given Ukrainian forces a Monday deadline to surrender control of the besieged port city of Mariupol, the scene of some of the heaviest fighting since Russia launched its invasion of Ukraine more than three weeks ago.

In a statement carried by Russian state news agency RIA Novosti, Moscow’s defence ministry said it was opening humanitarian corridors out of Mariupol from 10am local time on Monday and told Ukrainian forces defending the city to lay down their arms and leave. It demanded Kyiv respond in writing to its ultimatum by 5am on Monday.

Russia — which has framed its invasion as a “special operation” to “liberate” Ukraine — claimed Kyiv was using “Nazis”, “foreign mercenaries” and “bandits” to hold up to 130,000 civilians hostage. Despite overwhelming evidence to the contrary, it has denied any responsibility for the overwhelming civilian casualties in Mariupol and blamed them on “provocations” by Ukrainian nationalists.