Brussles, Mar 6 (AP) Facing the prospect that the United States might cut them adrift under President Donald Trump, European Union leaders launched a day of emergency talks Thursday in a bid to beef up their own security and ensure that Ukraine will still be properly protected.

Friedrich Merz, the likely next chancellor of Germany, and summit chairman Antonio Costa discussed over breakfast in Brussels ways to fortify Europe's defences on a short deadline.

Merz pushed plans this week to loosen the nation's rules on running up debt to allow for higher defence spending.

Meanwhile, the 27-nation bloc was waking up to news that French President Emmanuel Macron would confer with EU leaders about the possibility of using France's nuclear deterrent to protect the continent from Russian threats.

It all underscored the sea change that has taken place in the two months since Trump took office and immediately started questioning the cornerstones of cooperation between the United States and Europe that had been the bedrock of Western security since World War II.

“Given these profound shifts in US policy, and the existential threat of another war on the continent, Europe must manage its essential defence tasks,” the European Policy Center think tank said in a commentary.

The bloc will “take decisive steps forward," Macron told the French nation Wednesday evening. “Member states will be able to increase their military spending” and “massive joint funding will be provided to buy and produce some of the most innovative munitions, tanks, weapons and equipment in Europe,” he said.

Adding to the ebullient message, he said that “Europe's future does not have to be decided in Washington or Moscow.” Ukraine's President Volodymyr Zelenskyy is taking part in the summit.

Limited room to increase spending European Commission President Ursula von der Leyen has proposed a plan to loosen budget rules so countries that are willing can spend much more on defense. Her proposal is underpinned by 150 billion euros ($162 billion) worth of loans to buy priority military equipment.

Most of the increased defense spending would have to come from national budgets at a time when many countries are already overburdened with debt.

France is struggling to reduce an excessive annual budget deficit of 5% of GDP, after running up its total debt burden to 112% of GDP with spending on relief for businesses and consumers during the COVID-19 pandemic and the energy crisis that followed Russia's invasion of Ukraine.

Five other countries using the euro currency have debt levels over 100% of GDP: Belgium, Greece, Spain, Italy and Portugal.

Europe's largest economy, Germany, has more room to borrow, with a debt level of 62% of GDP.

Pressing security needs Part of any security plan is also to protect the increasingly beleaguered position of Ukraine.

A Russian missile killed four people staying at a hotel in Zelenskyy's hometown overnight. He said that a humanitarian organisation's volunteers had moved into the hotel in Kryvyi Rih, in central Ukraine, just before the strike. The volunteers included Ukrainian, American and British nationals, but it wasn't clear whether those people were among the 31 injured.

Early this week, Trump ordered a pause to US military supplies to Ukraine as he sought to press Zelenskyy to engage in negotiations to end the war with Russia, bringing fresh urgency to Thursday's summit.

Thursday's meeting is unlikely to address Ukraine's most pressing needs. It is not aimed at urgently drumming up more arms and ammunition to fill any supply vacuum created by the US freeze. Nor will all nations agree to unblock the estimated 183 billion euros ($196 billion) in frozen Russian assets held in a Belgian clearing house, a pot of ready cash that could be seized.

Still, the Europeans underlined the importance of the moment.

“Europe faces a clear and present danger on a scale that none of us have seen in our adult lifetime. Some of our fundamental assumptions are being undermined to their very core,” von der Leyen warned in a letter to the leaders ahead of their meeting.

But perhaps the biggest challenge for the EU will be to take a united stance at a moment when it's fractured, since much of what the bloc does requires unanimous support. Hungary is threatening to veto part of the summit statement on Ukraine.

Even if the challenges are so daunting, Thursday's summit is unlikely to produce immediate decisions on spending for Ukraine or its own defenses. Another EU summit where the real contours of decisions would be much clearer is set for March 20-21. (AP) AMS