World leaders on Thursday gathered in Normandy to remember those who fought and died on the beaches of northern France 80 years ago, when Allied forces launched "D-Day" to liberate Western Europe from Nazi occupation.

Moving letters from veterans were read as ceremonies kicked off to mark the 80th anniversary of the June 6, 1944 D-Day landings, when more than 150,000 Allied soldiers invaded France by sea and air.

US leader Joe Biden, French President Emmanuel Macron, Britain's King Charles III and Canadian Prime Minister Justin Trudeau, representing the Allied powers, paid tribute to the tens of thousands of troops who fought on the beaches.

Ukrainian President Volodymyr Zelensky arrived to attend the ceremonies and hold talks with the leaders -- a stark reminder of the conflict between his country and Russia.

The biggest guests of honour were some 200 surviving veterans in their late 90s or even over 100, some in wheelchairs, huddled in blankets as they gazed over the shores. (Agencies)