EU leaders agreed Friday that the bloc should take more responsibility for its own security, insisting Brussels needs to be a strong partner for NATO and the United States.
Debate has raged for decades over what role Brussels should play on defence, and individual nations have often been reluctant to agree moves to integrate military capabilities.
"We want to act more strategically, to defend our interests and to promote our values," European Council President Charles Michel tweeted after a video summit.
"We need to increase our ability to act autonomously and strengthen our cooperation with our partners."
NATO Secretary General Jens Stoltenberg joined the summit to talk up cooperation in the face of worries the EU's drive could undermine the US-backed alliance at a time new President Joe Biden is looking to strengthen it.
"We share very much the same population, the same members and the same neighbourhood and the same challenges," Stoltenberg said ahead of the encounter.
"It makes it absolutely obvious that we need to work together."
France is championing a push for "strategic autonomy" -- arguing the coronavirus pandemic, a resurgent Russia and former US leader Donald Trump's threats to cut off allies show Europe has to be able to stand alone.
"In the face of increased global instability, the EU needs to take more responsibility for its security," the leaders said in their official conclusions.
- 'A stronger EU' -
The 27 nations said they are looking to bolster the EU's partnership with NATO and work closely with the new US leadership under Biden.
"This global cooperation will benefit from a stronger EU in the field of security and defence," the statement said.
Leaders focused on a drive by Europe to better protect itself from cyber attacks, and asked Brussels to come up with a roadmap for boosting the development of strategic technologies.
French President Emmanuel Macron said Europe needed to "anticipate the new forms of threat; cyber, maritime, space, and air".
EU ambitions on common defence have gathered steam in recent years, and all but two nations signed up to the landmark PESCO (Permanent Structured Cooperation) pact in 2017 to increase cooperation.
The departure of Britain from the European Union saw the bloc lose some military and diplomatic heft, but also removed a fierce opponent of anything that might lead to a European army from the Brussels conversation.
The EU is seeking to implement a multibillion-euro fund to co-finance industrial defence projects and the five-billion-euro European Peace Facility (EPF), allowing it to provide military equipment and assistance to partner countries.
But key questions remain on how these projects will be implemented and the future of EU efforts.
The bloc's foreign policy chief Josep Borrell is trying to define a "strategic compass" so all nations can have a more united vision.
"We need to find a common understanding of the challenges and threats to European Union ... in order to propose ways to tackle them all together," he said.
- Macron questions NATO -
Diplomats say Brussels received backing from Biden's administration for its efforts when Secretary of State Antony Blinken spoke to EU foreign ministers on Monday.
Trump rattled NATO as he accused Washington's allies of underspending on defence and taking advantage of the US -- but Biden has declared the "trans-Atlantic alliance is back".
A senior EU official admitted the push for European autonomy has worried some in the bloc, who look towards NATO as a bulwark against a more aggressive Moscow.
"The capacity for the EU to act in a more autonomous way unnerves member states on the front line against Russia because they fear a disengagement from NATO," the official said.
Those nerves were reinforced last week when Macron again questioned if the transatlantic alliance was "still pertinent" in the post-Cold War world.
Those views have found little support, and leading economic power Germany remains firmly committed to NATO.
The alliance with North America, which includes 21 EU members, has been the bedrock for European security since it was founded over seven decades ago to confront the Soviet Union.