KIEV, Ukraine — Hopes that a local election could help shift tensions in an eastern Ukrainian city from simmering conflict to the relative safety of politics were thwarted Sunday when voters turned up to find no ballots.

The election in Mariupol, a strategically important city, had been called off even as the rest of the country voted. Electoral authorities in the Ukrainian-controlled portion of the Donetsk region said the ballots were flawed and there was no time to print new ones.

But critics quickly pointed out that opinion polls had shown that a political party affiliated with Ukraine’s former pro-Russian government had been poised to win the most votes.