More than 5,000 pro-Russia residents of a major city in Ukraine’s east demonstrated on Saturday in favour of holding a referendum on whether to seek to split off and become part of Russia.

The rally in Donetsk came less than a week after the Ukrainian region of Crimea approved secession in a referendum regarded as illegitimate by the Western countries. After the referendum, Russia moved to formally annex Crimea.

With Crimea now effectively under the control of Russian forces, which ring Ukrainian military bases on the strategic Black Sea peninsula, concern is rising that Ukraine’s eastern regions will agitate for a similar move.

Russia has brought large military contingents to areas near the border with eastern Ukraine. Russian President Vladimir Putin has said there is no intention to move into eastern Ukraine, but the prospect of violence between pro-and anti-secession groups in the east could be used as a pretext for sending in troops.

Eastern Ukraine is the heartland of Ukraine’s economically vital heavy industry and mining and the support base for Viktor Yanukovych, the Ukrainian president who fled to Russia last month after being ousted in the wake of three months of protests in the capital, Kiev.

Russia and Mr Yanukovych supporters contend his ouster was a coup and allege that the authorities who then came to power are nationalists who would oppress the east’s large ethnic Russian population.

“They’re trying to tear us away from Russia,” said demonstrator Igor Shapoval, a 59-year-old businessman. “But Donbass is ready to fight against this band which already lost Crimea and is losing in the east.”

Donbass is the name for the region of factories and mines that includes Donetsk.

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