Donetsk, Ukraine (CNN) -- Polls closed Sunday after voters streamed into polling stations in eastern Ukraine to vote in controversial referendums held by pro-Russian activists eager to declare independence from Kiev, an official said. Voters in the city of Donetsk faced this question on the ballot: "Do you support the Act of Independence of the People's Republic of Donetsk?" The options are "yes" or "no." A similar question is being put to voters in Luhansk. Many of the voters were not on the outdated registration lists but were allowed to vote after showing identification documents. There also seemed to be no system in place to prevent one person from voting at multiple polling stations. A CNN crew saw several people vote twice at one polling station, where the ballot boxes were decorated with new Donetsk independence flags. Photos: Crisis in Ukraine Russian military pride on full display Pro-Russian militants plan to defy Putin GPS: Did Putin plan the Crimea invasion? There was also a report of video showing three men arrested near Slovyansk with boxes of "yes" ballots in their car. But in a Sunday afternoon news conference, the head of the People's Republic of Donetsk Central Election Committee, Boris Litvinov, disputed reports that people were voting twice in some areas. Litivinov said the lines were so long that many people had a hard time voting once, let alone twice. He also denied the report about ballot fraud. Litvinov said there was no reason for pro-Russian activists to cheat because voter turnout was so high. The polls were told to stay open for 14 hours, rather than the usual 12, to allow time to add people to the voter list if necessary, the election committee said, adding that access to the most recent electoral rolls has been barred by Kiev. Litvinov was the official to announce that polls had closed. Results are expected later. Two incidents heightened tensions at polling places Sunday. Rubber bullets were fired into the air at a station in Donetsk, said election committee member Sergey Tretyakov. Tretyakov also said police in Krasnoarmeysk tried to prevent people from voting. The central government in Kiev has declared the polls illegal. Russia's mixed messages The message coming from Moscow on the referendum appears mixed. Russian police officers oversaw voting at a Moscow polling station erected for expat Ukrainians to vote in the Donetsk and Luhansk referendums. But last week, Russian President Vladimir Putin also urged the pro-Russian sympathizers to delay the referendum to give dialogue "the conditions it needs to have a chance." Putin's unexpected call appears to have dented the confidence of some pro-Russian activists. However, representatives of the pro-Russian groups in Donetsk and Luhansk voted to go ahead with it. Meanwhile, in Slovyansk, a Russian government-controlled TV channel was periodically showing a banner along the bottom of the screen that told viewers where they can vote in Sunday's referendum. That channel, Russia 24, is available over the air to residents of Donetsk, who can access it in their homes. The banner listed the location and voting hours and advised voters to bring a passport. The banner was shown only on the Russia 24 channel, not on other channels.