Slovakia's Prime Minister Robert Fico has threatened to end financial support for more than 130,000 Ukrainian refugees as a dispute with Ukraine over Russian gas supplies escalates.
On January 1 Kyiv shut down a pipeline which for decades has been used to supply Central Europe with Russian natural gas.
Slovakia was the main entry point and now the country stands to lose millions of euros in transit fees.
The United Nations Refugee Agency (UNHCR) calculated last month that there are 130,530 Ukrainian refugees in Slovakia out of 6,813,900 worldwide.
Fico – who in December made a surprise visit to Moscow for talks with Russian President Vladimir Putin – described Kyiv's move as “sabotage”.
The EU country's prime minister said he would propose a freeze on electricity exports to Ukraine, as well as a “sharp reduction” in financial support for Ukrainians who have taken refuge in Slovakia.
He said there was no risk of Slovakia itself suffering from gas shortages as it had already made alternative arrangements.
But Fico added that Ukrainian President Volodymyr Zelensky's decision to shut down the taps would deprive Slovakia of 500 million euros (£415 million; $518 million) in transit fees from other countries.
He said his party was ready to discuss “suspension of electricity supplies” and “significant reduction of support for Ukrainian citizens in Slovakia”.
“The only alternative for a sovereign Slovakia is to resume transit or require compensation mechanisms that will replace the loss in public finances,” he added.
Last month, Zelensky accused Fico of helping Putin “finance the war and weaken Ukraine.”
“Fico is involving Slovakia in Russia's attempts to cause more suffering to Ukrainians,” the Ukrainian president said.
Poland has offered to support Kiev if Slovakia cuts off electricity exports – supplies that are crucial to Ukraine, whose power plants are under regular attack from Russia.
Poland's government called the disruption “another victory” against Moscow, while the European Commission said the EU had prepared for the change and most countries could cope.
Moldova, which is not in the EU, is already suffering from shortages.
Russia can still send gas to Hungary, Turkey and Serbia via the Turkish Stream gas pipeline across the Black Sea.