President Donald Trump told the US's rattled allies that the bonds between them were "unbreakable" as they marked the 75th anniversary of the D-Day landings in northern France.
Trump joined other world leaders in northern France, as well as thousands of well-wishers, to pay tribute to the ever-dwindling number of veterans of the famed landings in 1944 that shaped the outcome of World War II.
"To all of our friends and partners, our cherished alliance was forged in the heat of battle, tested in the trials of war and proven in the blessings of peace. Our bond is unbreakable," Trump said in Colleville-sur-Mer.
The sober speech under bright blue skies appeared intended to reassure America's allies who have been shaken by Trump's "America First" policies and often aggressive rhetoric towards fellow leaders in Europe.
Trump also picked out several survivors of the Allied invasion by name to praise their courage in braving Nazi bullets during the biggest naval operation in military history on June 6, 1944.
About 60 of them, many in wheelchairs and sporting baseball caps, sat in rows behind Trump and French President Emmanuel Macron, who at one point helped one of the seniors to his feet to receive applause.
"We know what we owe to you, veterans: our freedom," Macron told the crowd in English. "And on behalf of my nation I just want to say thank you".
Macron, who has been an outspoken critic of Trump's nationalism and isolationist tendencies, also appeared to use the occasion to send a message to his American visitor.
"America is never as big as when it is fighting for the freedom of others," he said.
D-Day is seen as a great symbol of transatlantic cooperation, with thousands of young American servicemen joining Britons, Canadians and Australians in sacrificing their lives to end the Third Reich's grip on Europe.
By the end of what has become known as "the longest day", 156,000 Allied troops and 20,000 vehicles had landed in Nazi-occupied northern France on June 6, creating a vital bridgehead that would turn the war.
"The men behind me will tell you they are just the lucky ones," Trump said. "As one of them recently put it, all the heroes are buried here."
- Wellwishers -
Thursday's commemorations followed a gathering in Portsmouth, southern England, on Wednesday attended by Trump, Macron, Queen Elizabeth II, German Chancellor Angela Merkel and Canadian premier Justin Trudeau among others.
Earlier Thursday, Macron and British Prime Minister Theresa May laid the first stone for a new British memorial to fallen soldiers near the village of Ver-sur-Mer.
"Standing here as the waves wash quietly onto the shore below us, it's almost impossible to grasp the raw courage it must have taken that day to leap from landing craft and into the surf, despite the fury of battle," May said.
Many families of foreign servicemen as well as local French people flocked to cemeteries and commemoration sites on Thursday, regarding the occasion as perhaps a last chance to see many war veterans in the flesh.
"I attend the ceremonies every year, but the 75th anniversary is different, because we know that some of these people won't be around five years from now," Marcel Deschateaux told AFP in the town of Bayeux where Britain's Prince Charles attended a church ceremony.
- Macron and Trump talk -
Macron and Trump -- whose once warm relations have chilled due to mounting public disagreements on Iran, climate change and trade -- later met for a working lunch and private talks in the nearby town of Caen.
The last time Macron hosted Trump in France -- for the World War I centenary in November last year -- it turned into a diplomatic fiasco,
The real estate mogul arrived angry about Macron's support for a European army and he mocked the French leader on Twitter several days afterwards over his "very low approval ratings".
Trump conceded there had been ups and downs in their relationship.
"It's been good sometimes and sometimes it hasn't been, but right now it's outstanding. So the relationship that we've had together has been really terrific and I appreciate it very much," Trump told Macron in front of reporters.
Macron will end the day with an homage in the village of Colleville-Montgomery for the Kieffer Commando, the only French soldiers to storm a Normandy beach on D-Day which opened a new front against the Nazis and led to the liberation of France and much of western Europe.
The 177 men have long been little more than a footnote in France's official war history -- an oversight officials in Macron's office said he is eager to correct.
Trudeau will attend a ceremony at Juno Beach, where Canadian forces were in charge of the assault.
Russian President Vladimir Putin, who was invited to the 60th anniversary of the invasion in 2004, did not receive an invitation this time, in a snub indicative of the West's strained relations with Russia.
"We also don't invite everyone to every event. Why should I be invited everwhere?" Putin said on Thursday.
Russia's foreign ministry said Wednesday the Allied invasion on D-Day did not determine the course of World War II, and its importance should not be exaggerated.
The Soviet Union fought Hitler's troops from 1941 and leader Joseph Stalin was desperate for Britain and America to launch the Normandy invasion to relieve pressure on his soldiers on the eastern front.