Ukraine was "still ready" to continue negotiations with Moscow, which have stalled since the discovery of atrocities in Bucha and other areas near Kyiv, the Ukrainian President Volodymyr Zelensky said Saturday.

"Ukraine has always said it is ready for negotiations and looking for any way to stop this war," Zelensky said in a press conference with the Austrian Chancellor Karl Nehammer, who visited Bucha.

"Sadly, in parallel we see the preparations for important battles, some people say decisive ones, in the east," he said, referring to an anticipated Russian offensive.

"We are ready to fight and to look in parallel to end this war through diplomacy," he added.

The last face-to-face talks between the two sides took place on March 29, during which Ukrainian negotiators are said to have signalled their readiness to accept neutrality in return for security guarantees from third parties.

"In the east and in the south, we have seen a concentration of arms, equipment and troops who are getting ready to occupy another part of our territory," Zelensky said.

The outcome of any new Russian offensive would depend "on several factors", he said, including Ukraine's "strength, how quickly our partners supply us with arms, and the Russian leader's (Vladimir Putin) desire to go further."