June 5 (UPI) -- President Donald Trump joined Queen Elizabeth II and leaders of other allied nations Wednesday at Britain's Portsmouth Naval Base to commemorate the 75th anniversary of D-Day before the American leader headed north for a bilateral meeting with Irish Taoiseach Leo Varadkar.
In her final week as British prime minister, Theresa May hosted the leaders of 15 countries, including French President Emmanuel Macron, German Chancellor Angela Merkel and Canadian Prime Minister Justin Trudeau. The leaders issued a statement pledging to make sure the "unimaginable horror" of World War II doesn't happen again.
British Spitfires and other aircraft flew over the event. A Royal Navy ship fired a salute. Stories were retold of the some 5,000 ships, 11,000 airplanes and 150,000 soldiers that departed Portsmouth for the northern coast of France.
The invasion forces gathered there on June 5, 1944, preparing to take back Nazi-occupied France. More than 4,000 Allied service members died in the D-Day attack that turned the tide of the war. The D-Day landing occurred the following day, June 6, in Normandy, France. Numerous events are scheduled to observe the anniversary Thursday.
"At this time of reflection for veterans of the conflict and their families, I am sure these commemorations will provide an opportunity to honor those who made extraordinary sacrifices to secure freedom in Europe," the queen said. "They must never be forgotten."
Veterans who took part in the operation were honored for their bravery and some survivors attended to tell their stories. The cruise ship MV Boudicca was set to carry hundreds of veterans across the English Channel to retrace the journey they took 75 years ago. May will see the veterans off from the deck of the HMS Queen Elizabeth aircraft carrier.
"It is our chance, perhaps our last chance, to say thank you to these amazing individuals," said British defense minister Penny Mordaunt. "The courage that they showed, the immense scale of that is breathtaking and we should pause today to remember that and all those who are not here today."
Veteran Ernie Nelson was a telegraphist on the HMS Scourge, which escorted convoys to Sword beach and provided support to the troops when they landed.
"A lot of memories come back to me, that's the trouble," the 95-year-old said. "I get flashbacks, I remember the people I was with at that time."
Queen Elizabeth spoke about the resiliency of her generation and the fact that so many veterans got to attend the 75th anniversary.
"Seventy-five years ago, hundreds of thousands of young soldiers, sailors and airmen left these shores in the cause of freedom," Queen Elizabeth said. "In a broadcast to the nation at that time, my father, King George VI, said: ' .. what is demanded from us all is something more than courage and endurance; we need a revival of spirit, a new unconquerable resolve.' That is exactly what those brave men brought to the battle, as the fate of the world depended on their success."
On Tuesday, Trump said the D-Day landings "may have been the greatest battle ever in history."
Security for Wednesday's event was tight with so many world leaders in attendance -- most Portsmouth residents watched on large screens outside the cordoned off area.
"The global challenges we face today are different in their origin and nature," May said before the event. "But as we confront new and evolving threats to our national security, it is more important than ever that we continue to stand together in upholding our shared values and way of life."
After the event, Trump and first lady Melania Trump met with U.S. service members in Portsmouth before a luncheon. They then traveled to Ireland, where the president met with Varadkar at Shannon Airport.
Trump said he was confident Brexit negotiations would work out for the United Kingdom, and Ireland in particular. One of the major hangups in the negotiations is the border between Ireland and Northern Ireland.
"Probably you'll ask me about Brexit because I just left some very good people who are very much involved with Brexit as you know, and I think it will all work out very well," Trump said.
"And also for you, with your wall, your border. We have a border situation in the United States and you have one over here, but I hear it's going to work out very well."
Varadkar said Ireland wants to avoid a border or wall with Northern Ireland.
Trump said he hopes the United States and Ireland can agree on a working visa for Irish people to come to the United States. The president said there are "millions" of Irish people in the United States.
"I think I know most of them because they're my friends," he said. "We love the Irish, so it's an honor to be here."
Trump was expected to stay overnight at his golf resort in Doonbeg before traveling to France for D-Day anniversary events.