Europe should welcome rather than rebuff U.S. President Donald Trump's call for other NATO members to ramp up their military spending, Polish Prime Minister Donald Tusk said on Wednesday, stressing the importance of security to the continent.

The EU's top diplomat and Poland's prime minister said Wednesday that the bloc must heed US President Donald Trump's demand to spend much more on defence -- faced with the "existential threat" posed by Russia.

European Union leaders are warning that Russia could test the bloc's readiness to defend itself within the next three to five years, calling for an increase in defense budgets and deepen military cooperation among member states.

Intelligence services, as stated by the EU's chief diplomat Kaja Kallas, warn of a possible Russian attack starting in 2028. "Russia could test EU’s readiness to defend itself in three to five years," said the former Prime Minister of Estonia during an event organized by the European Defense Agency in Brussels.

European Union top diplomat Kaja Kallas warned on Wednesday of a possible attack by Russia in the coming years, as she appealed for defence spending to be boosted. "Many of our national intelligence agencies are giving us the information that Russia could test EU's readiness to defend itself in three to five years,