Image copyright AFP Image caption Roshen's owner Petro Poroshenko is a pro-European politician

Russian authorities have taken over a Ukrainian-owned sweet factory in the southern Russian city of Lipetsk, Ukraine's government says.

Russian riot police moved in on the Roshen factory and halted production on Wednesday, the finance and economic ministries said.

A spokesperson for the firm confirmed the "plant is closed".

Roshen is controlled by Ukrainian businessman and pro-European MP Petro Poroshenko.

He is planning to stand in May's presidential elections.

Ukraine's finance and economic ministries said Russian authorities had shown no documentation giving them the right "to burst on to the company's property and halt production".

Alexander Zolotarev, press spokesman for Roshen CIS, said the Lipetsk plant closed after police arrived and sent all the workers home.

'Chocolate war'

Last July, Russia's consumer watchdog banned sales of Roshen sweets, citing health concerns.

But many observers thought it to be Moscow's response to Mr Poroshenko's political activities rather than concern for the welfare of Russia's chocolate fans. The ban was eventually lifted in November.

Mr Poroshenko was among opposition figures in Ukraine who called for the country to resist Russia's invitation to join the Moscow-led Customs Union and instead integrate with Europe.

Image copyright AFP Image caption Petro Poroshenko has occupied top posts in Ukrainian politics

Ukraine's seventh richest man, according to Forbes magazine, with an estimated fortune of $1.3bn (£787m), Mr Poroshenko was a supporter of the Maidan protests that ultimately led to the overthrow of Ukraine's president Viktor Yanukovych last month.

The factory's closure comes at a time of high tensions between Ukraine and Russia following the outcome of Sunday's referendum in Crimea to secede from Ukraine and join the Russian Federation.

Angered by what is sees as Russian intervention on Ukrainian territory, the US and the EU are considering escalating sanctions against those it suspects of playing a part in the crisis.

Russia says Crimeans voted overwhelmingly to join the Federation and so the result of the referendum should be respected. Foreign Minister Sergei Lavrov said sanctions would be "illegitimate".