German Chancellor Angela Merkel and French President Emmanuel Macron took part in a memorial ceremony at the Compiegne forest, 90 kilometers (56 miles) northeast of Paris.
On the 11th hour of the 11th day of the 11th month, 1918, an initial agreement to end four years of one of the world's deadliest conflicts was signed by the Allies and Germany in a train carriage in a nearby forest clearing, from where the two leaders on Saturday held a symbolic repeat signing ceremony.
Merkel and Macron then watched as the French and German militaries held a joint march to remember the 1.4 million French and 2 million German soldiers killed in the 1914-1918 war.
Saturday's meeting was the first since 1945 between French and German heads of state at the location where the armistice was signed.
Read more: World War I: Europe and the politics of remembrance
'War to end all wars'The 'Great War' mobilized some 70 million military personnel as two European alliances fought a war that, at the time, wrought death and destruction on an unprecedented scale.
Some 40 million people were killed or injured in World War I — as many as 11 million of them were military personnel.
Earlier on Saturday, Canadian Prime Minister Justin Trudeau kicked off the weekend's solemn events with a visit to a cemetery in northern France containing the remains of 820 Canadian casualties from the 1914-1918 conflict.
Trudeau is one of 67 heads of state due to take part in the commemorations in France, which culminates with a ceremony at the Tomb of the Unknown Soldier in central Paris on Sunday morning. Two minutes of silence will be held around the world to remember those killed and wounded.
US President Donald Trump failed to make his planned visit to a US war cemetery outside Paris on Saturday due to "logistical difficulties caused by the weather," according to the White House. There was slight rain falling in the area.
Read more: How World War I ended: 100 years later
Steinmeier in LondonFurther armistice commemorations are being held all over the world this weekend, including in London, where on Sunday, German President Frank-Walter Steinmeier will become the first German head of state to take part in the annual wreath-laying ceremony at the Cenotaph war memorial.
Steinmeier will join Queen Elizabeth and British Prime Minister Theresa May at the solemn observance, which will be followed by a service at Westminster Abbey.
US President Donald Trump, meanwhile, was due to visit US military cemeteries in northern France on Saturday and Sunday, where many of the 110,000 American dead out of 4 million US troops mobilized during World War I are buried.
Trump met Macron at the Elysee Palace earlier on Saturday, shortly after blasting his French counterpart's plans to launch a European army as "very insulting."
The pair later played down any differences over the new European defense plan, with Macron insisting it was in line with Trump's repeated demands for European countries to pull their weight more in the Western military alliance NATO.
Read more: Games of Remembrance: Two armies mark WWI armistice centenary
Serbia holds war gamesSerbia, which is sometimes wrongly accused of starting World War I after a Serb nationalist assassinated the Austrian archduke in Sarajevo, Bosnia, in 1914, was holding large military drills on Saturday to mark the armistice centenary.
Commenting on the drill that involved some 8,000 troops, Serbian strongman Aleksandar Vucic said he was "overjoyed" by the display. He also announced more state investment into the armed forces and more armored transporters supplied by its traditional ally, Russia.
"I am very happy – everyone has seen the ground trembling with MiGs flying above, and when those 250-kilo (551 lb) bombs hit, half the hill was shaking," he told the Serbian national broadcaster.
The live-ammunition maneuvers, dubbed "The Century of Winners," are widely seen as a show of force amid rising tensions with neighboring Kosovo.
mm/jm (AFP, AP, dpa, Reuters)
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