Washington (AFP) – More than 100,000 flag-bearing bikers, many of them Vietnam veterans, throttled their engines Sunday for the annual “Rolling Thunder” ride through the capital as President Donald Trump vowed to keep the Memorial Day spectacle alive.

Spectators lined the route from the Pentagon to the National Mall to watch the growling parade of choppers, a leather-clad, red-white-and-blue tribute to American soldiers missing in the Vietnam War.

It had been billed as the last national Rolling Thunder ride by its organizers, but Trump, who loves a parade, appeared to offer a reprieve.

“The Great Patriots of Rolling Thunder WILL be coming back to Washington, D.C. next year, & hopefully for many years to come. It is where they want to be, & where they should be,” Trump tweeted from Japan.

The Great Patriots of Rolling Thunder WILL be coming back to Washington, D.C. next year, & hopefully for many years to come. It is where they want to be, & where they should be. Have a wonderful time today. Thank you to our great men & women of the Pentagon for working it out! — Donald J. Trump (@realDonaldTrump) May 26, 2019

“Thank you to our great men & women of the Pentagon for working it out!”

The Pentagon had no comment, referring questions to the White House, which offered no details on what had been worked out.

But Trump’s word was enough for Ron Galey, a Navy veteran who served in Vietnam in 1968-69 and has taken part in every Rolling Thunder ride since 1990.

“Trump said it’s not over, so it is not over, and he is the boss of those guys and he keeps his word,” he told AFP.

Many pro-Trump banners were visible among the bikers forming up for the parade.

The huge motorcycle rally began in 1988 with fewer than 3,000 participants under the motto “We will never forget.” The goal was to press for an accounting of those missing in Vietnam.

Over the years, it has grown into a rumbling combination of protest and parade.

Riders end up at the Vietnam Veterans Memorial and the nearby Lincoln Memorial for speeches and a concert on the eve of Memorial Day.

Unlike Veterans Day in the United States, which honors all military veterans in November, Memorial Day — on the last Monday in May — is aimed specifically at remembering those who died while serving in the US armed forces, were prisoners of war or remain unaccounted for.

The event has the same name as a major US bombing operation against North Vietnam during the war.

Bikers kicked off the weekend of events with a “blessing of the bikes” at Washington National Cathedral on Friday.

Organizers had cited difficult relations with the Pentagon — where riders line up to begin the rally — over logistics and costs, in announcing that this year would mark the last national rally.

“As always, the Pentagon is charging us with an outrageous bill for their services,” the group’s national president Joe Bean said in a letter to members.

Another letter co-signed by Bean said costs of staging the event had soared to more than $200,000.

“The organization will continue to bring awareness to the public, in years to come, with regional demonstrations,” organizers said in a statement on their website.

Trump, who was on an official visit to Japan, offered his support.

“Can’t believe that Rolling Thunder would be given a hard time with permits in Washington, D.C. They are great Patriots who I have gotten to know and see in action. They love our Country and love our Flag. If I can help, I will!” he said.

According to the Pentagon’s POW/MIA Accounting Agency, more than 82,000 US troops remain unaccounted for in wars as far back as World War II.