President Joe Biden told U.S. troops stationed in Britain on Wednesday that during his first overseas trip as commander-in-chief he will make clear to world leaders that “the United States is back” and that democracies of the world must rally together to confront the challenges of the day.

Biden made the declaration on Wednesday night at the Royal Air Force Mildenhall in Britain, about 90 miles northeast of London, during the first leg of the first overseas trip of his presidency – a trip in which he will aim to strengthen relations with close allies and promote democracy and multilateralism throughout the region.

Biden’s eight-day trip includes traveling to Britain, Belgium and Switzerland to meet politicians, royalty, NATO allies and hold summits with the Group of Seven (G7) nations, the European Union and Russian President Vladimir Putin amid heightened tensions following several high-profile cyberattacks originating from Moscow targeting the United States.

“The trip, at its core, will advance the fundamental thrust of Joe Biden’s foreign policy: to rally the world’s democracies to tackle the great challenges of our time,” national security adviser Jake Sullivan told reporters during a press conference on Monday.

“When President Biden returns to Washington next week, we believe that we will be in a materially stronger position to manage the major threats this country faces: Covid, climate, China, cyber, Russia and shaping the rules of trade and technology for the future,” he said.

Biden left Washington, D.C., early Wednesday and arrived in Britain at about 8 p.m. British Time (3 p.m. EDT), according to a White House schedule.

The president told the troops at the base that his administration is committed to leading with strength and defending U.S. values, with the goal of the trip to coalesce relations with European allies that share a history.

“America is better positioned to advance our national security and our economic prosperity when we bring together like-minded nations to stand with us,” said Biden. “These nations that have shed blood alongside of us in defense of our shared values,” he said.

“Our unrivaled network of alliances and partnerships that are the key to American advantage in the world and have been,” Biden added. “They’ve made the world safer for all of us, and they are how we are going to meet the challenges of today, which are changing rapidly. We’re going to meet it, though, from a position of strength.”

Biden told the troops that the alliance between the United States, Europe and Britain is a vital source of their strength and that during this trip he will ensure allies know that the United States will stand up to their defense.

“Here’s why this all matters so much right now,” he said. “I believe we’re at an inflection point in world history – the moment where it falls to us to prove that democracies will not just endure, but they will excel as we rise to seize the enormous opportunities of a new age,” he said.

The Bidens ended the day in St. Ives in Cornwall.

Sullivan, speaking with reporters before Biden’s speech, said the United States is taking additional steps to donate more coronavirus vaccine doses to developing nations and that they will use their leverage to have world democracies do the same.

“The president is focused on helping to vaccinate the world because it is the right thing to do,” he said. “It is what Americans do in times of need.”

He said Biden is to make the announcement Thursday, the same day the White House said he is scheduled to meet British Prime Minister Boris Johnson to “affirm the enduring strength of the special relationship” between the two countries. On Friday, he will attend the G7 summit in Cornwall on the southwestern tip of Britain.