COPENHAGEN, Oct 2, 2025 (BSS/AFP) - Ukraine's President Volodymyr Zelensky is set to join talks with leaders from across Europe in Copenhagen Thursday, as the EU seeks to bolster Kyiv's fight against Russia in the face of dwindling US support.

Heads of state and governments from just under 50 countries will converge on a conference centre under tight security after mystery drone flights rattled Denmark.

Zelensky arrives looking to rally support from his main remaining backers as US President Donald Trump has turned off Washington's taps on Kyiv.

Meanwhile European leaders are keen to work with Ukraine's war-tested expertise as they seek to bolster their own defences and build a "drone wall" to counter the menace from Moscow.

The drone incidents in Denmark and high-profile aerial incursions from Moscow in Estonia and Poland have heightened fears that Russia's assault on Ukraine could spill over Europe's borders.

"They are threatening us, and they are testing us, and they will not stop," Danish prime minister Mette Frederiksen warned after a first day of defence talks with leaders of the 27-nation European Union.

High on the agenda at Wednesday's summit was a proposal to use frozen Russian assets to fund a new 140-billion-euro loan for Kyiv.

Proponents say that move is needed to help Ukraine plug budget shortfalls -- and that Russia, not European taxpayers, should ultimately foot the bill.

"It is only fair that Russia pays for its violation and destruction," said Frederiksen.

"Our support to Ukraine is a direct investment in our own security, and therefore we have to deliver long term financing of Ukraine's armed forces," she added.

Belgium, where the vast majority of frozen assets are held, is still asking a lot of questions over the plan.

EU chief Ursula von der Leyen said it was clear that risk should not fall only on Belgium's shoulders and that Brussels would "intensify" talks on the proposal.

- Orban blockage -

As he headed to the summit, Zelensky urged the EU "to keep its promises" to Ukraine on its bid to join the bloc, even as Hungarian leader Viktor Orban stalls Kyiv's push.

Officials in Brussels and Kyiv say Ukraine has carried out the necessary legal legwork to make more progress on negotiations, but Budapest is refusing to budge.

European Council chief Antonio Costa has been canvassing support for a plan that would mean countries cannot veto each new step of talks.

But Orban appeared to pour cold water on the project as he gave a firm "no" when asked if Ukraine had any prospects of joining the bloc soon.

"It would mean, first, that war would come into the European Union. Second, money from the European Union would go to Ukraine," Orban said in Copenhagen Wednesday.

Another area where the Hungarian leader is proving an outlier in the EU is its efforts to end purchases of oil and gas from Russia.

Trump has demanded that NATO allies stop purchasing fossil fuels from Moscow before he will move ahead with sanctions to pressure the Kremlin to end the war in Ukraine.

Hungary, along with neighbouring Slovakia, is one of the few European Union countries to still import oil from Russia via a pipeline.

Orban, one of Trump's strongest backers in the EU, insisted that landlocked Hungary can't stop buying from Russia -- but that argument isn't going down well.

"Those who choose ties with Russia instead of America, are going against both Europe and the US," Zelensky told EU leaders by videolink Wednesday.

"We truly hope that guys from Hungary will listen to these shared signals from all of us."