Hungary and Slovakia have asked the European Commission to mediate a consultation procedure with Ukraine, Hungary's foreign minister said on Monday, after Kyiv placed Russian group Lukoil on a sanctions list, stopping its supplies to the two countries, Paralel.Az reports citing Reuters.

Slovakia and Hungary have stepped up pressure on Kyiv after they said last week they had stopped receiving oil from Lukoil via Ukraine. Hungary receives 2 million metric tonnes of oil from the Russian group annually, around a third of its total oil imports, Peter Szijjarto said.

"I spoke with the Ukrainian foreign minister yesterday, he said they allow every oil transfer through, but it's not true," Szijjarto told reporters while in Brussels.

The two countries have now initiated a consultation with the European Commission, he said. "The Commission has three days to execute our request, after which we will bring the issue to court."

Szijjarto said if the consultation procedure did not bear fruit, Hungary and Slovakia will bring the issue to an international court of their choosing instead.

In an attempt to sell the freed-up crude volumes, Lukoil has added some 140,000 metric tonnes of crude oil to its original lifting plan for the Black Sea port of Novorossiis for July, market sources said.

Lukoil's oil supplies via Druzhba's southern spur account for some 50% of the pipeline's flows. MOL's refineries in Slovakia and Hungary totally depend on supplies from Lukoil.

As an alternative, Hungary may import oil from Croatia's Omisalj sea port via the Adria pipeline, while Slovakia is landlocked and is only able to get oil via Hungary.

Since April, oil imports via Omisalj were at around 500,000 metric tons each month. Supplies include such oil grades as Basrah, Azerbaijan's BTC and CPC Blend.

Russia continues to supply natural gas and oil to landlocked Hungary and Slovakia via Ukraine despite the war in the country and existing EU sanctions on Russian crude.

The countries have exemptions from oil sanctions to give them more time to transition to alternative sources of supply.

Both Slovakia and Hungary also supply energy to Ukraine. Szijjarto said Hungary provided 42% of Ukrainian electricity imports last month.

Slovakia's Prime Minister Robert Fico said over the weekend that his country helped supply diesel to Ukraine, in comments in which he blasted the sanctions and said Slovakia would not be "hostage" to Ukraine-Russia relations.

On Monday Slovak Foreign Minister Juraj Blanar reiterated some of Fico's comments, saying that the sanction had a bigger impact on the Slovakia and the EU than Russia itself.

Ukraine's ban does not affect other Russian oil exporters whose oil was still allowed to transit through Ukraine.