World leaders look up for a family photo at the opening of the Paris Peace Forum after the commemoration ceremony for Armistice Day.

:: World leaders marking the centenary of the armistice that ended World War I in France on Sunday later attended the Paris Peace Forum where they warned that world peace may be under threat.

The forum in Paris a three-day conference aimed at promoting concrete actions toward peace and encouraging multilateralism.

French President Emmanuel Macron who opened the Peace Forum said that the world’s stability is threatened by nationalism, racism, antisemitism and extremism, as well as by economic, environmental and migrants-related challenges.

Macron said that the meeting of 84 world leaders at a ceremony in Paris to commemorate the armistice is a historic moment.

In his speech Macron said “what is important for the future is the way this image will be interpreted”: As the “symbol of durable peace between nations” or as “a picture of a last moment of unity before the world goes down in new disorder.”

“It depends only on us”, he added.

The Paris Peace Forum aims at promoting concrete actions toward peace and should be repeated every year, he said.

German Chancellor Merkel

For her part, German Chancellor Angela Merkel has made an impassioned plea for world peace and cooperation 100 years after Germany’s defeat in World War I, saying “we must not simply stand by and watch” as more conflicts continue to unfold around the world.

Speaking at the Peace Forum, Merkel denounced the “national vain gloriousness and military arrogance” that led to the “senseless bloodshed” of two world wars.

She warned against taking peace for granted, saying: “We have to work for it.”

In a veiled dig at US President Donald Trump’s America-first policies and skepticism toward multilateral cooperation, Merkel warned that “lack of communication and unwillingness to compromise” can have deadly consequences.

UN Secretary-General Antonio Guterres

For his part, the head of the United Nations warned during his speech that the world today has several of the ingredients that led to the failure of the peace that followed World War I.

Guterres noted trade conflicts, increasingly polarized politics, and the failure to solve inequalities exposed by the 2008 world financial crisis.

He expressed particular concern about the “crisis of confidence” in the European Union, calling the bloc forged from the ashes of World War II a project “too meaningful to fail.”

He acknowledged problems at the UN, but stressed its importance to averting a world war for the past 73 years.

Guterres also cautioned about a “weakening of the spirit of compromise that underpins democracies, an indifference to collective rules.”

US President Donald Trump, who has expressed disdain for multilateral organizations, skipped the event.

UN Secretary-General Antonio Guterres during his speech in Paris.