People demonstrate Ukrainian passports as they stand in a line to enter a polling station and take part in the referendum on the status of Donetsk and Luhansk regions in Moscow May 11, 2014. Rebels pressed ahead with a referendum on self-rule in east Ukraine on Sunday and fighting flared anew in a conflict that has raised fears of civil war and pitched Russia and the West into their worst crisis since the Cold War.

Mariupol - Residents of two restive regions in eastern Ukraine engulfed by a pro-Russian insurgency are casting ballots in contentious and hastily organised independence referendums.

Sunday's ballots seek approval for declaring so-called sovereign people's republics in the Donetsk and Luhansk regions, where rebels have seized government buildings and clashed with police and Ukrainian troops.

Polling stations opened at 8 a.m. (07:00 SA time) and were due to close at 10 p.m. (21:00 SA time).

Referendum organisers have said they expect a high turnout.

Ukraine's authorities and the West have rejected the referendums as illegal.

Ukraine's interim president has said that independence for eastern regions will destroy the country's economy. - Sapa-AP