European Union leaders have backed plans for a new defence network against Russian drones following recent incursions into European airspace.
At a summit in Denmark's capital, Copenhagen, leaders expressed support for a so-called drone wall, an EU-wide system of detection and tracking of drones, with the potential for them to be shot down.
The plan will be subject to further negotiations ahead of a formal summit in three weeks' time.
As the talks took place, French troops boarded a Benin-flagged oil tanker off the coast of France, which is suspected of being the launch pad for drones that closed a number of airports, including Copenhagen, last week.
They arrested two crew members of the tanker, according to France's Prime Minister Sebastien Lecornu.
Its crew is accused of failing to provide proof of the vessel's nationality and failing to comply with orders.
The drone incidents in Denmark and high-profile aerial incursions from Russia in Estonia and Poland have heightened fears that Moscow's assault on Ukraine could spill over Europe's borders.
Danish Prime Minister Mette Frederiksen warned that Russia is engaged in a hybrid war against Europe, using sabotage, disinformation and airspace incursions.
"They are threatening us, and they are testing us, and they will not stop," she said.

There were intense discussions on a plan to use frozen Russian assets for a €140 billion loan to fund Ukraine militarily.
Proponents say the move is needed to help Kyiv plug budget shortfalls and that Russia, not European taxpayers, should ultimately foot the bill.
"It is only fair that Russia pays for its violation and destruction. Our support to Ukraine is a direct investment in our own security, and therefore we have to deliver long term financing of Ukraine's armed forces," ," Ms Frederiksen said.
Belgium, where the vast majority of frozen assets are held, is continuing to question the plan.
European Commission President Ursula von der Leyen said it was clear the risk should not fall only on Belgium's shoulders and that talks would "intensify" on the proposal.
There is no consensus as yet, nor is there a breakthrough in changing EU rules that would help Ukraine circumvent a Hungarian veto in its accession process.
President Volodymyr Zelensky urged the bloc "to keep its promises".
Officials in Brussels and Kyiv say that Ukraine has carried out the necessary legal legwork to progress negotiations, but Hungarian Prime Minister Viktor Orbán is refusing to budge.
President of the European Council Antonio Costa has been canvassing support for a plan that would mean countries cannot veto each new step of talks.
But Mr Orban appeared to pour cold water on the project as he gave a firm "no" when asked if Ukraine had any prospects of joining the EU soon.
"It would mean, first, that war would come into the European Union. Second, money from the European Union would go to Ukraine," he said.

Another area where the Hungarian leader is proving an outlier in the EU is its efforts to end purchases of oil and gas from Russia.
US President Donald Trump has demanded that NATO allies stop purchasing fossil fuels from Moscow before he will move ahead with sanctions to pressure it to end the war in Ukraine.
Hungary, along with neighbouring Slovakia, is one of the few EU countries to import oil from Russia via a pipeline.
Mr Orban, one of Mr Trump's strongest backers in the bloc, insisted that landlocked Hungary cannot stop buying from Russia.
"Those who choose ties with Russia instead of America, are going against both Europe and the US," President Zelensky responded.
"We truly hope that guys from Hungary will listen to these shared signals from all of us."
Ukraine will again be top of the agenda today for the seventh meeting of the European Political Community, a pan-continental twice yearly gathering of EU and non-EU leaders.
President Zelensky will address the gathering and hold a news conference with Ms Frederiksen, the Danish government said in a statement.
The two leaders met this morning.
Meanwhile, Taoiseach Micheál Martin will have bilateral meetings with the leaders of Norway and Molodova.
Additional reporting AFP, Reuters