RIGA/KIEV, April 4 (Reuters) - Ukrainian President Petro Poroshenko on Tuesday refused to back down over Kiev’s decision to ban Russia’s entry for this year’s Eurovision Song Contest, despite a threat from the organisers to throw Ukraine out of future competitions, though not the one due in May.

Relations between Ukraine and Russia have been toxic since Russia’s annexation of Crimea in 2014 and the outbreak of separatist violence in the Donbass region.

Their antipathy spilled over into the Eurovision contest after Ukraine’s entry Jamala won last year with a song about Stalin’s mass deportation of ethnic Tatars from the Crimean peninsula during the Second World War.

Having won the right to host this year’s event, Ukraine banned 27-year-old Russian singer Yulia Samoylova from entering its territory on the grounds that she has visited Crimea without Ukraine’s permission.

Russia said the Ukrainian move tarnished the event, while Eurovision’s organisers wrote a letter, leaked to the media, to Ukrainian Prime Minister Volodymyr Groysman threatening to exclude Ukraine’s state broadcaster from future events.

Speaking to reporters in Riga, Poroshenko said Russia had put forward its contestant as a deliberate provocation.

“The Ukrainian authorities did not fall for this provocation,” Poroshenko said. “We act consistently as regards everyone who violates Ukrainian legislation,” he said, according to a statement on the president’s website.

The European Broadcasting Union has offered the possibility of the Russian singer participating from outside Ukraine via satellite link. The proposal was made to Russia’s Channel One, which rejected the idea.

Ukraine’s state broadcaster on Tuesday urged the EBU to respect the country’s sovereignty and to drop its threat to shut Ukraine out of future competitions.

In a statement published on its website, the broadcaster urged the EBU not to be used as “an instrument of strengthening foreign political manipulations”.

Ukraine expects about 12,000-14,000 spectators to attend the competition in May, with millions more watching on television. It will be the second time that Kiev has hosted the event.

The war between Ukraine and Russian-backed separatists has killed more than 10,000 people. The two sides agreed to honour a ceasefire on April 1 but this quickly broke down.