Ukrainian President Volodymyr Zelenskyy warned that if 'negotiations' with Russian President Vladimir Putin fail then 'that would mean that this is a third World War'.
"I'm ready for negotiations with him. I was ready for the last two years. And I think that without negotiations we cannot end this war," reported CNN.
"I think that we have to use any format, any chance in order to have a possibility of negotiating, possibility of talking to Putin. But if these attempts fail, that would mean that this is a third World War," he added.
The humanitarian situation in Ukraine's south-eastern city of Mariupol continued to worsen as thousands of civilians were estimated to be killed in the city since the beginning of hostilities, even as Russian and Ukrainian forces trade charges over who is to blame for the deplorable situation.
The Russian military has reportedly offered the Ukrainian troops defending Mariupol to lay down arms and exit the city via humanitarian corridors, but that proposal was quickly rejected by the Ukrainian authorities.
Russia's defence ministry has consistently levelled charges of serious human rights violations on the Azov battalion of the Ukrainian armed forces.
The Azov battalion has been alleged to consist of 'neo-Nazi' Ukrainian nationalist elements.
"There is a terrible humanitarian catastrophe in Mariupol as a result of the lawlessness brought about by Ukrainian nationalists. Desperate and mindless bandits, realizing the impossibility of receiving any assistance from Kyiv, terrorize those neighbourhoods of the city that are still under their control," the head of the Russian National Defence Control Center, Mikhail Mizintsev, said on Sunday.
He added that the Ukrainian nationalists in the besieged city are killing between 80 and 235 civilians that try to flee each day, Sputnik news agency reported.
"It has been established that from 80 to 235 innocent citizens die every day at the hands of the Nazis, this is a terrible statistic for the last three days only. These are the people that are trying to leave the city on their own, the militants simply shoot them," Mizintsev said.
The Russian official went on to say that up to 130,000 civilians are being held hostage by Ukrainian nationalists in Mariupol.
Mizintsev said on Sunday that all Ukrainian soldiers could leave the Azov Sea port on Monday using safe routes for evacuating civilians and head to areas controlled by the Ukrainian authorities.
He said that 'all those who lay down arms will be guaranteed a safe exit from Mariupol'.
Meanwhile, Ukraine's Deputy Prime Minister Iryna Vereshchuk said in remarks carried by Ukrainska Pravda news outlet that Kyiv already had told Russia that 'there can be no talk about surrender and laying down weapons'.
She rejected the Russian statement as 'manipulation'.
The Ukrainian authorities have accused Russia of bombing civilian sites including a theatre sheltering civilians and an art school.
Mariupol City Council, who had shared an image of the destroyed theatre building, said Russian forces had 'purposefully and cynically destroyed the Drama Theater in the heart of Mariupol', CNN reported.
At the same time, Thousands of Mariupol residents who managed to escape from Russian bombs are starving to death in occupied Manhushi and Melekin.
The Head of Donetsk Military-Civil Administration, Pavlo Kyrylenko claimed on Sunday said that the Russian occupying forces are refusing to provide food, water and safe passage.
'Head of Donetsk Military-Civil Administration, Pavlo Kyrylenko, said thousands of Mariupol residents who managed to escape from Russian bombs are starving to death in occupied Manhushi and Melekin. Russian occupying forces refuse to provide food, water and safe passage,' tweeted The Kyiv Independent.
The coastal city of Mariupol has seen some of the most brutal fighting in the ongoing conflict between Russia and Ukraine.
As many as 2,500 civilians have died in Mariupol, Ukrainian officials estimate, and hundreds of thousands of people are trapped in the city -- with officials warning those who remain are without electricity, water and heat, CNN reported.
Russia has been facing immense pressure from the international community to stop its military operations in Ukraine which has created an immense humanitarian crisis with thousands of refugees from Ukraine fleeing to the neighbouring countries to the west.
-- with inputs from Agencies
