Ukraine's lead negotiator said on Tuesday it was hard to predict when peace talks might resume because of Russia's siege of Mariupol and what he portrayed as Moscow's desire to strengthen its position through a new military offensive.
Kyiv and Moscow have not held face-to-face talks since March 29nd, and the atmosphere has soured over Ukrainian allegations that Russian troops carried out atrocities in a town near Kyiv. Moscow has denied the accusations.
Mykhailo Podolyak, Ukraine's top negotiator, told Reuters the continuing siege of Mariupol and the repeated failure of attempts to arrange safe corridors for the evacuation of trapped Ukrainian civilians had also complicated matters.
"Obviously, against the backdrop of the Mariupol tragedy, the negotiation process has become even more complicated," he said in a written response to questions about peace talks.
"Russia defiantly renounces any manifestations of humanity and humanism when it comes to certain humanitarian corridors. Especially when we talk about Mariupol."
Each side blames the other for the breakdown of peace talks and the failure of negotiations on safe corridors for civilians.
Podolyak said some contacts were continuing online to "clean up" agreements reached on future guarantees for the security of Ukraine, ensuring they were compliant with international law.
"It is difficult to say when the next face-to-face round of negotiations will be possible because the Russians are seriously betting on (making gains in) the so-called 'second stage of the special operation'," he said.
Local authorities say thousands of people have been killed in the siege of Mariupol, and Russia have given the last Ukrainian defenders holed up in a steel works an ultimatum to surrender or die. Podolyak said Russia wanted to crush the last fighters in Mariupol for "internal propaganda" purposes.
Russia denies targeting civilians in its "special operation" which it says is intended to demilitarise Ukraine and root out dangerous nationalists, and says the defenders of Mariupol include far-right fighters. Kyiv and the West dismiss Russia's stance as a pretext for an unprovoked invasion.
Moscow has accused Ukraine of faking atrocities to undermine peace talks which President Vladimir Putin said on April 12th had come to a dead end.
Ukrainian troops this month showed journalists corpses of what they said were civilians killed by Russian forces in the town of Bucha outside Kyiv after Russian troops retreated. Reuters saw dead bodies in Bucha but could not independently verify who was responsible for the killings.