COLLEVILLE-SUR-MER, France — The United States and its allies will keep providing “significant” support to Ukraine out of respect for the legacy of D-Day soldiers, whose victory over the Nazis helped lead to a new world order and a “better peace,” Army Gen. Mark Milley, chairman of the Joint Chiefs of Staff, said Monday.

In an interview with The Associated Press overlooking Omaha Beach in Normandy, Milley said Russia’s war on Ukraine undermines the rules established by Allied countries after the end of World War II. He spoke on the 78th anniversary of the D-Day invasion of Allied troops onto the beaches of France, which led to the overthrow of Nazi Germany’s occupation.

One fundamental rule of the“global rules-based order” is that “countries cannot attack other countries with their military forces in acts of aggression unless it’s an act of pure self-defense,” he stressed. “But that’s not what’s happened here in Ukraine. What’s happened here is an open, unambiguous act of aggression.”

“It is widely considered to undermine the rules that these dead — here at Omaha Beach and at the cemetery at Colleville-sur-Mer — have died for. They died for something. They died for that order to be put in place so that we would have a better peace,” Milley said, speaking at the American Cemetery overlooking the shore in the northwestern French village at Colleville-sur-Mer.

That’s why “the nations of Europe, the nations of NATO, are supporting Ukraine with lethal and nonlethal support in order to make sure that that rule set is underwritten and supported,” Milley explained.

Dozens of veterans — now all in their 90s, from the U.S., Britain, Canada and elsewhere — were taking part in poignant D-Day ceremonies Monday.

On June 6, 1944, Allied troops landed on French beaches code-named Omaha, Utah, Juno, Sword and Gold, carried by 7,000 boats. On that single day, 4,414 Allied soldiers lost their lives, 2,501 of them Americans. More than 5,000 were wounded. On the German side, several thousand were killed or wounded. The massive invasion helped lead to Hitler’s defeat and the end of World War II.

Asked about whether Ukraine gets enough support, Milley noted “there’s a very, very significant battle going on in the Donbas,” in reference to Ukraine’s heavily contested eastern industrial region bordering Russia. “But Kyiv (the capital) was protected and successfully defended against. The Russians had to shift their forces to the south in the Donbas. And we’ll see how this plays out.”

“I think that the United States and the allied countries are providing a significant amount of support to Ukraine, and that will continue,” he said. He didn’t elaborate.

Milley also had strong words about Ukraine at the ceremony at the American Cemetery, attended by over 20 World War II veterans and several thousand spectators.

“Kiev may be 2,000 kilometers away from here, they too, right now, today, are experiencing the same horrors as the French citizens experienced in World War II at the hands of the Nazi invader,” Milley said in his speech. “Let’s not those only here be the last witnesses to a time when our Allies come together to defeat tyranny.”

Milley’s parents served during World War II and his uncle was in the Navy off Normandy’s coast on D-Day as part of Operation Overlord.

That generation of soldiers “fought and sacrificed for all of us… And I have a very, very special bond with them. And I’m very respectful of what they’ve done. And I think we all — all of us today — need to carry on the legacy that they fought and died for,” Milley said.