France’s president, Emmanuel Macron, has appealed directly to Donald Trump to fulfil the “promise of Normandy” by embracing pillars of the postwar peace such as the European Union and Nato as the two leaders marked the D-day landings 75 years ago. 

In a speech that trod a fine diplomatic line, Macron offered both sincere expressions of gratitude for the valour of US troops in the second world war and vehement calls for the White House to re-engage with the principles of multilateralism. 

Speaking in front of 15,000 people gathered at the American cemetery and memorial in Colleville-sur-Mer, the resting place for 9,387 US troops killed in the Normandy campaign, Macron repeatedly name-checked Trump, even at times turning to face the US president who was sitting behind him. 

“Dear Donald Trump, the United States is never greater than when it is fighting for the freedom of others,” Macron said from a stage erected by a wall of the missing. “ The United States of America is never greater than when it shows its loyalty.  Loyalty to the universal values that the founding fathers defended, when nearly two and a half centuries ago France came to support its independence.  What we owe you is to show ourselves worthy of the heritage of peace that you have left us. 

Facebook Twitter Pinterest Melania and Donald Trump and Emmanuel and Brigitte Macron watch a flypast.  Photograph: Carlos Barría/Reuters

“Being worthy of the promise of Normandy means never forgetting that free people, when they join forces, can surmount any adversity,” Macron went on. “ We shall never cease to perpetuate the alliance of free peoples.  That is what the victorious sides did, when they created the United Nations, the North Atlantic Treaty Organization.  That is what a few years later the leaders of Europe did in bringing about the European Union.  The lessons of Colleville-sur-Mer are clear: liberty and democracy are inseparable.” 

Trump, who has described Nato as obsolete in the past and had used this week’s state visit to the UK to spend time with leading lights of the Brexit camp such as Nigel Farage, offered no visible reaction to Macron’s comments beyond an awkward smile. 

Macron had leavened his overtly political speech with repeated emphasis of France’s thankfulness and sense of obligation to those who fought and died to liberate his country and the rest of Europe from Adolf Hitler’s Germany. 

“On behalf of France, I bow down before their bravery,” Macron said before bestowing five of the veterans at the ceremony, all now in their 90s, with the Légion d’honneur, France’s highest award. “ We know what we owe to you veterans: our freedom.  On behalf of my nation I just want to say: thank you.” 

Facebook Twitter Pinterest The presidents greet veterans.  Photograph: Ian Langsdon/Pool/EPA

When it came to Trump’s turn to speak, the president told the stories of some of those on the stage who had been part of the D-day landings on 6 June 1944, when 73,000 US troops landed at Utah and Omaha beaches as part of Operation Overlord, the codename given to the land, naval and air operations that remain the largest amphibious operation ever waged. 

Quick guide What happened on D-day?  Show Hide What was D-day?  D-day was an invasion of France by allied forces.  It was codenamed Operation Neptune, and it aimed to push Nazi Germany out of occupied France.  Five beaches in Normandy, codenamed Omaha, Utah, Juno, Sword and Gold, were the main targets for landing a large number of troops by sea.  At 10pm on 5 June 1944, troops began departing from British shores to head across the Channel.  Five assault groups set sail under darkness in an armada of about 7,000 vessels.  Just after midnight on 6 June, aerial bombardment of enemy positions on the Normandy coast began.  Special operations troops were also parachuted into France.  US troops landed on Omaha and Utah beaches at about 6:30am.  About an hour later Canadian forces landed at Juno, and British troops landed at Gold and Sword.  Soldiers had to get off their boats, wade through the water, and seize control of the beach, all the while under heavy and sustained fire from German defensive positions.  How was the plan kept secret?  Despite involving a large number of troops, keeping D-day secret was vital to the success of the operation.  A disinformation campaign had led the Germans to believe that Operation Fortitude was the main plan for the allies to invade the continent, via a two-pronged attack involving Norway and Calais.  Even once the D-day landings had begun, German commanders were convinced they were just a diversionary tactic before the real invasion.  Why is it called D-day?  The D in D-day actually has no particular significance to Operation Neptune.  It was common practice in the military to make plans that used the term, where the D stands for the day when operations commenced.  Military planners also set H-hour, the time at which a plan was to begin.  What happened next?  By the end of the day, the allies had disembarked more than 135,000 men and 10,000 vehicles on to the beaches, and established bridgeheads of varying depths along the Normandy coastline.  This came at the cost of 4,400 allied troops being killed, with thousands more injured or missing.  There were also heavy casualties among German troops and French civilians.  By 19 August, the allied forces had pushed down far enough to begin the battle to liberate Paris.  German troops surrendered the French capital on 25 August 1944, two and a half months after D-day.  Martin Belam

The American cemetery, spread across 70 hectares (172.5 acres) of landscaped acres, overlooks Omaha beach, where on D-day alone about 3,000 US troops were killed, wounded or reported missing. 

Play Video 1:58 D-day 75th anniversary: world leaders pay their tributes – video highlights

Among the 35 veterans on the stage who stepped on to the beaches of Normandy 75 years ago was Russell Pickett, the sole survivor now of Company A of the 29th Division, 116th Regiment, which suffered 96% casualties within half an hour of battle on Omaha beach, made infamous by the opening scenes of the Hollywood film Saving Private Ryan. 

As the two leaders personally thanked Pickett, Trump steadied and hugged the 94-year-old as the veteran appeared to stumble as he got up from his seat. 

Facebook Twitter Pinterest Russell Pickett at Omaha beach.  Photograph: Rafael Yaghobzadeh/AP

Trump also emphasised the achievements of the generation in America that liberated Europe and then went on to defeat communism and put a man on the moon. 

“The men behind me will tell you that they are just the lucky ones,” he said. “ As one of them recently put it, all the heroes are buried here.  But we know what these men did.  We know how brave they were.  They came here and saved freedom.  And then they went home and showed us all what freedom is all about.” 

In typical fashion Trump added: “And today, America is stronger than ever before.” 

The US president did, however, appear to offer some reassurance to those worried by his scepticism about the value of multilateral organisations. 

“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,” he said. “ Our bond is unbreakable.” 

After the speeches, Macron and his wife, Brigitte, walked among the veterans who had sat behind them to hear their stories.  The Normandy event, like others in France and the UK, is widely seen as being one of the last great remembrance ceremonies at which the generation involved in the D-day landings is likely to be in attendance in significant numbers. 

Facebook Twitter Pinterest The Trumps and Macrons at the US cemetery.  Photograph: Ian Langsdon/AP

The Trumps also shook some hands when talking to the veterans but then awkwardly waited at the side of the stage for the Macrons before both couples walked to a vantage point overlooking Omaha beach to spend a minute in silence before watching a flypast of French and US planes. 

Trump and Macron held 30 minute private talks in Caen, the nearby French city heavily bombed during the invasion. 

A French official said the mood between the two presidents was constructive.  Trump stressed that – although the US-France relationship might have had its ups and downs in the past – “right now it is outstanding”. 

Macron said the legacy of the Normandy beaches lived on in shared values, with the two countries working “to preserve democracy and freedom”, in joint military action in west Africa and in Middle East diplomacy. 

Issues discussed included the approach to Iran after the US withdrew from a nuclear deal and reimposed harsh economic sanctions. 

Addressing reporters, Trump sought to play down differences on Iran, saying neither he nor France wanted Iran to have nuclear weapons. 

Macron said: “We share the same objectives on Iran … First, they don’t get nuclear weapons … Second, we want to reduce their ballistic activity, third, to contain them regionally.  The fourth common objective, after all, is peace in the region.  We want to deliver those objectives together.  That is the point and all the other debates are about technicalities.”