New York, Nov 12: US President Donald Trump has paid tribute to all the American veterans - currently numbering at some 18 million - in an emotional message at the traditional Veterans Day Parade in New York.

Trump, the first sitting President to participate in the event, which on Monday commemorated the 100th anniversary of the end of World War I and the beginning of the traditional parade, said that it was time to acknowledge the sacrifice of all soldiers, Efe news reported.

Attending the event, which took place in Lower Manhattan and was the largest parade of its kind in the US, were veterans of various wars in which the US has participated, along with New York Mayor Bill de Blasio, as well as New York chief of police James O'Neill, Senator Chuck Schumer, First Lady Melania Trump and Eric Trump, the President's son.

The President, who addressed about 200 people before the start of the parade organized by the United War Veterans Council and in which some 25,000 people marched along Fifth Avenue, recalled the end of World War I.

He said that in 1919, the streets of New York filled with excited citizens to welcome Gen. John Pershing, who had led the US Expeditionary Force in World War I, along with 25,000 American troops.

"The men and women who have donned our nation's uniforms are the bravest, toughest, strongest and most virtuous warriors ever to walk on Earth," he said.

"You left your families and fought in faraway lands. You came face-to-face with evil and you did not back down. You returned home from war and you never forgot your friends who didn't return, including prisoners of war and those missing in action.

"This nation is forever in your debt, and we thank you all... You are the reason our hearts swell with pride, our foes tremble with fear, and our nation thrives in freedom," the President added.

Trump also reviewed all the conflicts in which the US has been involved and praised the effectiveness of US troops, including in response to the 9/11 terrorist attacks and the recent military operation in Syria in which Islamic State (IS) leader Abu Bakr al-Baghdadi was killed.

"Thanks to American warriors, al-Baghdadi is dead. His second-in-charge is dead. We have our eyes on No. 3. His reign of terror is over, and our enemies are running very, very scared," Trump said.

"Those who threaten our people don't stand a chance against the righteous might of the American military," he continued.

He promised US veterans that the nation would never forget those who guard the country's freedoms.

During the event, a minute of silence was observed to mark the 100th anniversary of World War I and a floral offering was placed in Madison Square Park, where Trump spoke.

Shortly after that the military parade began, which was also participated in by New York Governor Andrew Cuomo, another harsh critic of Trump.

This is the first visit Trump has made to New York - where he was born and lived for decades before winning the presidency - since he changed his official residence from that state to Florida, where he will enjoy significant tax advantages.

According to Trump, he made that decision because the political leaders of New York City and New York state have treated him "very badly."

During Trump's remarks, signs were visible in the windows of nearby skyscrapers saying "Lock him up" and similar messages, referring to the impeachment investigation now under way in the House of Representatives.

Several dozen people also gathered close to Madison Square Park displaying banners and signs reading "Traitor, criminal, lock him up!", Sexist in chief" and "Impeach Trump" and chanting these and other slogans.

Trump honours veterans at 100th anniversary of NY parade