President Donald Trump has hailed the “brave men and women” of the US military in a speech at an Independence Day event in Washington DC.
“We celebrate our history, our people, and the heroes who proudly defend our flag,” he told a crowd at the Lincoln Memorial.
Armoured carriers and tanks are part of the “Salute to America” event.
Opponents accuse him of politicising the holiday ahead of a re-election campaign and wasting taxpayer’s money.
The Pentagon has not revealed the cost of the extravaganza, which many believe was inspired by Mr Trump’s visit to the Bastille Day parade hosted by French President Emmanuel Macron.
Some reports say the National Park Service is diverting nearly $2.5m (£2m) to cover the cost.
What is happening?
“Together we are part of one of the greatest stories ever told, the story of America,” Mr Trump said at the event.
“It is the chronicle of brave citizens who never give up on the dream of a better and brighter future,” he told the crowd, which had braved heavy rain and hot temperatures.
The president added: “As long as we never stop fighting for a better future… there will be nothing that America cannot do.”
As well as tanks, Mr Trump’s 4 July celebration features a military jet flyover and an extended fireworks show.
As the armoured vehicles were transported from a railyard in south-eastern Washington DC on Tuesday evening, military officials advised residents not to be alarmed.
The two 70-tonne Abrams tanks have to stay on a side road as they are too heavy for the memorial’s surrounding areas.
In a morning tweet, Mr Trump said the parade was “turning out to be one of the biggest celebrations in the history of our Country”.
He will be keeping a keen eye on the turnout, given the arguments over the claimed attendance of his inauguration ceremony back in 2017.
The event is open to the public free of charge, apart from a ticketed area for VIPs in front of the memorial.
Large numbers of Trump supporters wearing Make American Great Again hats – and opponents upset at the cost – have descended on the capital.
Trump supporter Brandon Lawrence told Reuters: “I think what Trump’s doing with the tanks, all the flyovers, I think it’s great.”
Critic Medea Benjamin said: “This is costing us millions and millions of dollars. We the taxpayers are paying for it, for Donald Trump to use our military as a prop.”
The musical playlist includes the Star Wars theme and Hail to the Chief.
The event has been largely good-humoured, although there were scuffles outside the White House earlier on Thursday after a flag-burning protest.
Americans gather to catch a glimpse
By Harry Low, BBC News, Lincoln Memorial
“Who doesn’t love America’s birthday?” Andrea Stanford (second from right) beams.
The 58-year-old is one of the “Women 4 Trump” group who travelled for 15 hours from Florida with her friends. All of whom, she revealed, are wearing red, white and blue underwear. Why?
“Donald Trump is redefining the presidency and the commitment to freedom and liberty,” she says.
“He’s the first president whose kept his promises – economically and militarily,” she added, referring to the recent meeting at the DMZ with North Korean leader Kim Jong-un.
Alongside the reflecting pool, where rain drops have been crashing down all afternoon, people from states across this country have filed in. Utah, Indiana and Washington state are all represented, many of them wanting to catch a glimpse of the president.
One African American man from Maryland wore a President Obama hat and said he simply wanted to celebrate the national holiday with his fellow Americans.
Mr Trump is being joined by a Pentagon delegation led by the highest-ranking US military officer, Chairman of the Joint Chiefs of Staff General Joseph Dunford.
But the service chiefs of the Army, Navy, Air Force and Marine Corps are not attending.
The defence department said in a statement it had received 5,000 tickets from the White House.
The White House has also distributed VIP tickets to major donors and political appointees, amid reported concerns that empty seats might be visible.
Mr Trump’s re-election campaign sent out an email this week encouraging supporters to attend the event. But the Democratic National Committee has been given no tickets.
And the cost?
Mr Trump said in a tweet that the expense “will be very little compared to what it is worth”.
Military flyovers alone cost tens of thousands of dollars per hour.
Mr Trump’s plans for a military display on Veterans Day in November last year were dropped after defence officials said it would cost about $92m – more than three times the original estimate.
What have opponents said?
They see it as an inappropriately partisan display and a misuse of public funds.
US presidential contender Joe Biden and two other Democratic candidates marched instead in Iowa, which kicks off the nomination race in seven months’ time.
Senator Bernie Sanders wrote on Twitter: “This is what authoritarians do: Donald Trump is taking $2.5 million away from our National Park Service to glorify himself with a spectacle of military tanks rolling through Washington.”
Protesters have brought along an inflatable balloon depicting Mr Trump as a baby but have been denied permission to use helium to make it airborne.
Harry Truman was the last president to speak before a large crowd on the Washington Monument – in 1951.