Washington, Jan 20 (IANS): Donald Trump pledged unity and promised a change that America has not seen in decades, as he spoke in front of a crowd of thousands in Washington, D.C., on his final day as President-elect.

"I promise you that I will work so hard. We're gonna get it turned around," Trump told supporters while speaking on the steps of the Lincoln Memorial on Thursday evening, pledging to bring back American jobs, build up the military and strengthen the nation's borders.

"We're going to do things that haven't been done for our country for many, many decades. It's going to change. I promise you. It's going to change," Politico quoted the real-estate mogul as saying.

Trump traded in his beloved private plane for a military jet earlier on Thursday and arrived in Washington with his family for three days of festivities, CBS News reported.

Accompanied by Vice President-elect Mike Pence, Trump started his day by laying a wreath at the Arlington National Cemetery on the Tomb of the Unknown Soldier, marking the formal beginning of the end of their transition to the White House.

Trump spoke for a little more than six minutes at the Lincoln Memorial, echoing much of his campaign rhetoric: He hailed his campaign as a "movement" that's never been seen before, recounted how it started in June 2015, rattled off estimates of the massive crowd sizes from his past rallies, reminded supporters that this is their movement and that he was merely the messenger, and vowed to unify the country.

He thanked the performers at his "Make America Great Again" welcome celebration and his family for their support, and said his transition team had the idea to host a concert at the Lincoln Memorial, which he suggested may never have occurred before.

In fact, President Barack Obama held his inauguration concert in 2009 at the Lincoln Memorial.

"So many people have poured into Washington, D.C. This started out tonight being a small little concert, and then we had the idea, ‘Maybe we'll do it in front of the Lincoln Memorial,'" Trump said.

"I don't know if it's ever been done before, but if it has, very seldom. And the people came by the thousands and the thousands, and here we are tonight, all the way back."

Trump arrived at the Lincoln Memorial with much fanfare, drawing chants of "Trump!" from the thousands of supporters before The Frontmen of Country - Tim Rushlow, Larry Stewart and Richie McDonald - performed a medley of their greatest hits, including Trump's campaign song, "God Bless the USA", with country star Lee Greenwood, Politico reported.

The concert featured country singer Toby Keith, rock band 3 Doors Down, Indian origin DJ Ravidrums and veteran Hollywood actor Jon Voight, among others.

This was followed by a black-tie pre-inauguration dinner where in between acknowledgements to his staff and jibes at former presidential hopeful Hillary Clinton, he spoke of Friday's swearing in ceremony, joking that if it rains as predicted, at least the taunts about his gravity-defying hair might stop, the Daily Mail reported.

Meanwhile, several hundred anti-Trump protesters set off fires on the street near a celebration by his supporters called the DeploraBall, a name inspired by Hillary Clinton's description of some Trump supporters as "deplorables", at the National Press Club Building in Washington and police in riot gear retaliated with pepper spray.

The police said that there were no serious injuries or arrests at the incident.

About 900,000 people are expected to be at his inauguration on Friday, either as participants or protesters. Homeland Security Secretary Jeh Johnson told the media that 28,000 law enforcement personnel will be deployed.

The President-elect and future First Lady are expected to spend their last night before taking public office at Blair House, as is tradition, before Trump is sworn in on Friday.

Friday morning Trump will first go to a church and then visit the White House. From there, he and President barack Obama will then go to the Capitol for the swearing-in.

Chief Justice John Roberts will swear-in Trump, who will place his hands on a Bible he used as a child and another that belonged to late President Abraham Lincoln.

As the newly minted President he is to walk from there with his family to the White House and occupy the symbol of the presidency.