BRATISLAVA, Slovakia (AP) -- Slovakia's populist leader on Wednesday blasted a European Union plan to halt imports of Russian natural gas by the end of 2027 to deprive President Vladimir Putin of revenue that helps fuel the war in Ukraine.

The European Commission, the bloc's executive branch, will present a detailed plan next month. It will seek to ban new gas contracts with Russia by the end of this year and phase out existing ones still in use in the 27-nation EU by the end of 2027.

Prime Minister Robert Fico said that the plan is "absolutely unacceptable" for Slovakia. He said that his government was ready to veto it and all Slovak representatives involved in the negotiations on the EU level would work to stop it.

Fico said that the move would be harmful for Slovakia and the entire EU, because the price of gas will increase as a result. His country has a gas delivery deal with Russia that expires in 2034, and Fico said that he would seek compensations for damages, if the plan proceeds.

The Slovak leader also rejected a proposal to halt imports of oil and nuclear fuel from Russia to the EU.

Hungary and Slovakia -- whose leaders are considered to be Putin's closest allies in Europe -- have blocked EU military assistance to Ukraine and have been expected to oppose the European Commission's gas plans.

Fico, who is a divisive figure at home and abroad, returned to power in 2003 after his leftist Smer (Direction) party won a parliamentary election on a pro-Russia and anti-American platform. Known for his pro-Russia views, he has openly challenged the EU's policies over Ukraine.

He is set to become the only EU leader to travel to Moscow for festivities on Friday marking the 80th anniversary of the defeat of Nazi Germany in World War II. It will be his second trip to Moscow since December.

His government has faced vocal protests against its pro-Russian stance and other policies.