KYIV (Reuters) - The mayor of Ivano-Frankivsk in western Ukraine urged residents on Thursday to avoid public gatherings this weekend, or leave the city if they can, for fear of Russian missile strikes.

       His announcement followed warnings by Ukrainian officials that Russia might step up its offensive in Ukraine before May 9, when Moscow commemorates the Soviet Union's victory over Nazi Germany in World War Two.

       Mayor Ruslan Martsinkiv said in a video posted online that he had cancelled all official events in Ivano-Frankivsk on Saturday, Sunday and Monday.

       "We have certain information, the enemy unfortunately wants to conduct further missile strikes, therefore on the 7th, 8th, and 9th there won't be any public events, including prayers," he said. "For your safety, I urge you ... on these three days to stay at home ... or out of town if you are able."

       He cited no evidence for the assertion that there could be missile strikes and gave no details of the "information" he referred to.

       Russia did not immediately comment on his remarks. Moscow has denied targeting civilians and has said its military actions in Ukraine are not tied to a specific date.

       The Kremlin has dismissed speculation that President Vladimir Putin might declare war against Ukraine on May 9. He characterises Russia's actions as a "special military operation".

       Ukraine's defence ministry said on Wednesday Russia was trying to accelerate its offensive in the east of the country, but a Ukrainian presidential aide said on Thursday he did not expect Russia to achieve any "significant results" by May 9.

       In a further sign of unease in Ukraine before Russia marks "Victory Day", local authorities in the southern city of Zaporizhzhia said a curfew would be enforced from 7 p.m. on May 8 until 5 a.m. on May 10.

       (Reporting by Natalia Zinets and Max Hunder, Editing by Timothy Heritage)