WASHINGTON, June 7 (AFP) - Joe Biden will fight what he calls a "defining" battle for democracy on his first foreign presidential trip, meeting top US allies in Europe ahead of a tricky summit with Russia's Vladimir Putin.

The busy agenda - with G7, NATO and European Union summits ahead of the Putin sit-down in Geneva - will see Biden fly the flag for a West he sees at an "inflection point".

"This is a defining question of our time," Biden wrote in The Washington Post ahead of his trip.

"Will the democratic alliances and institutions that shaped so much of the last century prove their capacity against modern-day threats and adversaries? I believe the answer is yes. And this week in Europe, we have the chance to prove it."

Biden's pitch marks a return to a traditional US worldview after four years during which Donald Trump flirted with autocrats and recast multilateralism as a dirty word.

Biden meets G7 partners - Britain, Canada, France, Germany, Italy, Japan - from Friday to Sunday at a seaside resort in south-west England, then visits Queen Elizabeth II at Windsor Castle.

From there he flies to Brussels for NATO on Jun 14 and the EU meeting on Jun 15 before heading to see Putin, whom Biden recently characterised as a "killer," in Switzerland.

That choreography - by far the most intense travel schedule since the 78-year-old took office - is designed to send a clear message to Putin: Biden will represent a democratic bloc, not just the US.

"He will go into this meeting with the wind at his back," National Security Advisor Jake Sullivan said.