Focus sharpened on the threat this week after unidentified drones forced Denmark to shut some of its airports.

EU defence commissioner Andrius Kubilius held online talks with ministers from some 10 EU states mainly along the bloc's eastern border, with Denmark joining after the drone incidents there.

Ukraine -- which has developed a raft of capabilities to detect and shoot down Russian drone swarms more cheaply -- also took part.

"The repeated violations of our airspace are unacceptable. The message is clear: Russia is testing the EU and NATO. And our response must be firm, united, and immediate," Kubilius told a news conference in Helsinki after the talks.

"At today's meeting, we agreed to move from concept to concrete actions."

Kubilius said ministers backed a broad plan to bolster the EU's eastern defences and said the "immediate priority" should be a "drone wall, with advanced detection, tracking, and interception capabilities".

Ukraine's defence minister Denys Shmygal said his country was "ready to participate" in the project.

"The drone wall will create a fundamentally new defence ecosystem in Europe, of which Ukraine is ready to be a part," he wrote on social media.

- Polish incursion -

EU officials say the initial focus would be to develop a network of sensors to help better detect any incursions.

They say the aim is to have that first stage ready within a year -- but building capabilities to intercept the drones would take longer.

EU chief Ursula von der Leyen made a first call for the "drone wall" in a keynote speech earlier this month, hours after NATO shot down Russian drones in Poland.

The NATO response to Russia's drone incursion in Poland showed up the gaps in the alliance's arsenal for tackling that threat.

NATO had to use top-of-the-range fighters firing costly missiles to shoot down a handful of cheap Russian drones.

The alliance has rushed more hardware to its eastern flank in the wake of the incident, but still lacks the sort of low-cost capabilities Ukraine uses.

The "drone wall" proposal is part of Europe's broader push to bolster its defences in the face of the threat from Russia.

Kubilius has said the programme should be one of the new flagship defence projects that the bloc is working on.

EU leaders are set to debate the defence push -- and potential new initiatives -- at a summit in Copenhagen next week.