The two Brussels-based organisations have been looking to improve coordination for years, despite fears in some quarters that efforts to bolster the EU's role in defence could undermine the US-led alliance.

The invasion of Ukraine has spurred calls to better harness the combined clout of Europe's economic muscle and US military might to better protect the one billion citizens living in member states.

"This is a key juncture for Euro-Atlantic security and stability, more than ever demonstrating the importance of the transatlantic bond, calling for closer EU-NATO cooperation," said the statement, which is to be released by top NATO and EU officials on Tuesday.

"As the security threats and challenges we are confronted with are evolving in scope and magnitude, we will take our partnership to the next level."

The declaration points to tackling "growing geostrategic competition", protecting critical infrastructure, and dealing with threats from emerging technologies and in space as important areas for deeper cooperation.

Twenty-one of the European Union's 27 member states are already in NATO, and Sweden and Finland are currently pushing to join.

The statement says the bodies "play complementary, coherent and mutually reinforcing roles in supporting international peace" and pledged to "further mobilise" their political, economic and military strength.

It will be signed by NATO's Secretary General Jens Stoltenberg, the president of the European Council Charles Michel and the European Commission Ursula von der Leyen.

Efforts led by France to boost the EU's role in defence have caused jitters among Eastern European states who see Washington as the mainstay of their security.

Since Moscow's invasion in February, Washington has bolstered its troop numbers in Europe to over 100,000 personnel as NATO conducts the largest overhaul of its defences since the end of the Cold War.

The joint declaration -- the first since 2018 -- makes it clear that the alliance "remains the foundation of collective defence" for its members and the broader Euro-Atlantic area.

But it also says, "we recognise the value of a stronger and more capable European defence that contributes positively to global and transatlantic security and is complementary to, and interoperable with, NATO."

The US has long been pushing its European allies to spend more on their militaries, take on cyber threats and bolster infrastructure around the continent that is needed to shift forces quickly.

Washington has also been pressing Europe to take a tougher stance on the perceived threat posed by China's growing might.

"China's growing assertiveness and policies present challenges that we need to address," the joint declaration says.