MOSCOW (AP) — Ukraine's security service says it has prepared documents to ban Russia's contestant from this year's Eurovision song contest, but that a final decision has not been made.

Russia chose Yulia Samoylova to represent the country in the May 11-13 contest in Kiev.

But Samoylova has toured in Russia-annexed Crimea, without entering it by going through the de-facto border with the Ukrainian mainland. Under Ukrainian law, that allows authorities to block her entry into Ukraine.

Ukrainian Security Service official Oleksander Tkachuk said authorities have prepared documents to block Samoylova's entry for some time, adding: "We will make the decision in the near future."

Allowing Samoylova to compete would likely anger Ukrainian nationalists, but banning her could aggravate tensions with Russia already extreme over Crimea and the Russia-backed insurgency in east Ukraine.