KYIV (Reuters) - Ukraine on Saturday denied suggestions that it was refusing to negotiate a ceasefire with Russia but said it was also not ready to accept ultimatums or unacceptable conditions.

       Mykhailo Podolyak, an adviser to the office of Ukrainian President Volodymyr Zelenskiy, told Reuters Ukraine has prepared a negotiating position but was faced with impractical negotiating conditions from Russia.

       "It was yesterday that the aggressive actions of the armed forces of the Russian Federation escalated, up to evening and night mass air and missile strikes on Ukrainian cities," he said in a message. "We consider such actions only an attempt to break Ukraine and force it to accept categorically unacceptable conditions."

       (Reporting by Pavel Polityuk; writing by Matthias Williams; Editing by Catherine Evans)