Russian forces have withdrawn from Chernobyl, the site of the world's worst nuclear disaster, the state enterprise overseeing Ukraine's nuclear power plants said on Thursday, March 31, according to CNN.

"It was confirmed that the occupiers, who seized the Chernobyl nuclear power plant and other facilities in the Exclusion Zone, marched in two columns towards the Ukrainian border with the Republic of Belarus," said Energoatom in a statement published on Telegram.

On April 26, 1986, an explosion ripped through the No.4 reactor at Chernobyl, killing 30 people immediately. Countless others died from radiation symptoms in the years that followed.

Also Thursday, fresh efforts were made to evacuate civilians trapped by Russian forces in the Ukrainian city of Mariupol, the BBC reports.

Ukrainian Deputy Prime Minister Iryna Vereshchuk said a convoy of 45 Ukrainian buses was on its way to the besieged southern city.

She said the International Committee of the Red Cross (ICRC) had confirmed that Russia had agreed to open a humanitarian corridor to Mariupol.

Tens of thousands of civilians remain there after weeks of bombardment.

Vereshchuk also accused Russian troops of blocking the bus convoy at a checkpoint near Vasylivka, three hour's drive from Mariupol, earlier in the day.

"The Russian Federation, again, does not let our buses pass," she told Ukrainian news agency Unian.