Ukraine has banned a Russian singer from entering the country to compete at the Eurovision Song Contest over a past performance in Russia-annexed Crimea, the Ukrainian security service (SBU) said Wednesday.

"The Security Service of Ukraine has banned Yuliya Samoilova from entry for three years," SBU spokeswoman Olena Gitlyanska said. "The decision was taken just now."

Gitlyanska added the ban had been imposed because Samoilova had been "in violation of Ukrainian legislation."

A wheelchair user, Samoilova performed at the 2014 Paralympic Winter Games in Sochi, as well as at a gala concert in Crimea aimed at popularising sport in June 2015.

Russia's participation in the Kiev contest in May is fraught with political tensions as the two ex-Soviet neighbours have been locked in a bitter feud since Moscow annexed Crimea in March 2014.

Ukraine had condemned the choice of the singer as a Russian "provocation," while the Kremlin insisted it opposed "politicising" the contest.