Ukraine indicated on Wednesday it would bar French presidential candidate Marine Le Pen from entering the country after comments she made that appeared tolegitimise Russia's annexation of Crimea in 2014.
Le Pen's office dismissed the threat, saying she had no intention of visiting Ukraine.
Kiev is nervous about the shifting political landscape in 2017. U.S. President-elect Donald Trump has adopted a friendlier tone towards Russia while another French presidential candidate, Francois Fillon, favours lifting sanctions against Moscow.
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Relations between Ukraine and Russia soured after Russia's annexation of Crimea and the subsequent outbreak of pro-Russian separatist fighting in eastern Ukraine that has killed around 10,000 people, despite a ceasefire being notionally in place.
Alluding to Le Pen, the Ukrainian foreign ministry said in a statement: "Making statements that repeat Kremlin propaganda, the French politician shows disrespect for the sovereignty and territorial integrity of Ukraine and completely ignores the fundamental principles of international law.
"...Such statements and actions in violation of the Ukrainian legislation will necessarily have consequences, as it was in the case of certain French politicians, who are denied entry to Ukraine," it said.
The far right leader was quoted by French television as saying Russia's annexation of Crimea was not illegal because the Crimean people had chosen to join Russia in a referendum, a position Kiev vehemently disputes. The referendum was also declared illegal by the United Nations General Assembly.
Opinion polls have consistently shown Le Pen making it to the second round of the presidential election, to be held in May, but losing that run-off to a mainstream candidate, likely to be conservative Fillon.
"Marine Le Pen had no intention of going there (to Ukraine) anyway. This issue will be solved via diplomatic channels when she becomes president of the (French) Republic," a spokesman for Le Pen said in an emailed response to Reuters.
Earlier on Wednesday Le Pen said France should leave the euro but the shift to a new national currency could be accompanied by a framework similar to the pre-euro era of the ECU.