U.S. President Joe Biden departs for Britain on Wednesday on his first trip abroad since taking office, an eight-day mission to rebuild trans-Atlantic ties strained during the Trump era and to reframe relations with Russia .

The trip represents a test of the Democratic president's ability to manage and repair relationships with major allies who grew disenchanted with then-President Donald Trump's trade tariffs and withdrawal from international treaties.

"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 said in an opinion article published in the Washington Post.

His summit with Russian President Vladimir Putin on June 16 in Geneva is the capstone to the trip, an opportunity to raise U.S. concerns directly with Putin about ransomware attacks emanating from Russia, Moscow's aggression against Ukraine and a host of other issues.

Biden will make his first stop at the seaside village of St. Ives in Cornwall where he will participate in the G7 summit. The meeting is expected to be dominated by vaccine diplomacy, trade, climate and an initiative for rebuilding infrastructure in the developing world. U.S. officials see that effort as a way to counter China's growing influence.

Biden may face pressure to do more to share U.S. vaccine supplies with other countries after an initial pledge of 20 million doses announced last week.

His push for a global minimum tax on multinational corporations faces opposition at home. G7 finance ministers agreed before the summit to pursue a global minimum tax rate of at least 15% and to allow market countries to tax up to 20% of the excess profits - above a 10% margin - generated by about 100 large, high-profit companies.

Republicans came out against the plan this week, potentially complicating the U.S. ability to implement a broader global agreement.

Biden will have a meeting with British Prime Minister Boris Johnson on Thursday in Cornwall, a chance to renew the U.S.-British "special relationship" after Britain's Brexit break from the European Union.

After three days of G7 summitry, Biden and his wife Jill will visit Queen Elizabeth at Windsor Castle. The 78-year-old Biden met the queen back in 1982 when he was a U.S. senator from Delaware.

Afterwards Biden travels to Brussels for talks with leaders of NATO and the European Union. The agenda is expected to be dominated by Russia, China and the perennial issue of getting NATO allies to contribute more to the common defense.

Biden closes out the trip in Geneva for what could prove to be the most difficult meeting of the week - a session with Putin, who had enjoyed friendly relations with Trump.

White House national security adviser Jake Sullivan told reporters that Biden hoped his G7 and NATO meetings will bolster a sense of allied unity as he goes into his session with Putin.

No major breakthroughs are expected from the summit. Sullivan said Biden would press Putin on U.S. priorities. The two sides were negotiating whether to hold a joint news conference.