Voting offices were closed on Sunday for a local election in the key port city of Mariupol, the government's last bastion in rebel-held eastern Ukraine, an official told AFP.

"Polling stations did not open in Mariupol because the ballots were not ready in the voting offices. The election must be delayed because some of the ballots had serious problems," said Natalia Kachtchi, a member of the local electoral commission.

An AFP journalist in central Mariupol confirmed that the doors of voting offices were shut Sunday morning.