European security

Brexit casts doubt over new EU and NATO defense strategy

Britain's departure from the European Union risks undermining Europe's new defense strategy, days before NATO and EU governments sign a landmark pact to confront a range of threats from Russia to the Mediterranean, officials say.

The European Union and the United States plan to use two separate EU and NATO summits in the coming days to push reforms of the West's two main security pillars, aimed at reducing Europe's reliance on Washington in its own neighborhood.

"Things are going to be a lot harder," said a senior Western defense official involved in EU-NATO cooperation. "NATO planned on linking itself up to a stronger European Union, not being the default option for a weakened, divided bloc."

Facing a more aggressive Russia, a migrant crisis and failing states on its borders, the European Union needs to "act autonomously if and when necessary", EU foreign policy chief Federica Mogherini will tell EU leaders on Tuesday as she unveils a five-year global strategy plan seen by Reuters.