The US military has told Washington DC residents not to panic if they see tanks on the streets for President Donald Trump's Independence Day parade.
At least two Bradley armoured carriers and two M1A1 Abrams tanks will be moved to the heart of the US capital for the president's "Salute to America".
The National Park Service will reportedly divert nearly $2.5m (£2m) to cover the cost of the event.
Mr Trump tweeted his 4 July celebration will be "the show of a lifetime".
Our July 4th Salute to America at the Lincoln Memorial is looking to be really big. It will be the show of a lifetime!— Donald J. Trump (@realDonaldTrump) July 3, 2019
What will happen?
As well as tanks, Mr Trump's 4 July celebration will feature a military jet flyover, an extended fireworks show and speech by the president at the Lincoln Memorial.
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.
Army Col Sunset Belinsky told a local CBS News affiliate that residents of the capital city "will see the vehicles move through their neighbourhoods, but should not panic".
Col Belinsky did not disclose where the tanks would be displayed on the National Mall in the city centre.
"The Pentagon & our great Military Leaders are thrilled to be doing this," Mr Trump said in a tweet on Tuesday. "Incredible Flyovers & biggest ever Fireworks!"
But the weather forecast is threatening to rain on Mr Trump's parade. Afternoon and evening thunderstorms are predicted for Thursday.
The event will be open to the public free of charge, apart from a ticketed area for VIPs in front of the Lincoln Memorial.
Mr Trump will be joined on Thursday 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 will not attend.
The Defence Department said in a statement it had received 5,000 tickets from the White House.
Both the Republican National Committee and Mr Trump's campaign confirmed to US media they had also received passes to hand out.
The White House has reportedly distributed VIP tickets to major donors and political appointees.
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 for the event.
Partisan or patriotic?
During the Obama administration, a routine military exercise in Texas fostered all manner of fevered talk of an impending military coup. Now tanks are arriving in the nation's capital, Air Force jets are planning a show of force and the US Army is telling local residents not to be alarmed.
Conspiracy theorists have been largely silent, however. It's a sign of how much has changed in just a few years.
Mr Trump's "Salute to America", despite being hastily planned, is - like his presidency itself - a norm-breaking development. It's a military-draped political rally on the ground where Martin Luther King Jr once gave his "I Have a Dream" speech.
The Republican Party is distributing tickets to VIPs, the president is planning an address and the financially strapped National Park Service has diverted funds for the event.
Democrats are up in arms about the politicisation of a holiday best known for neighbourhood parades, a kitschy musical show near the Capitol and fireworks displays large and small.
The president will dismiss such criticism as unpatriotic and revel in the glow of military might. And, like all Trump-related conflagrations, this will burn bright but eventually fade away.
Or maybe it will rain.
How much will it cost?
Trump administration officials have not disclosed how much taxpayers' money will be used for the 4 July celebration. But military flyovers alone cost tens of thousands of dollars per hour.
Mr Trump said in a tweet that the expense "will be very little compared to what it is worth".
The cost of our great Salute to America tomorrow will be very little compared to what it is worth. We own the planes, we have the pilots, the airport is right next door (Andrews), all we need is the fuel. We own the tanks and all. Fireworks are donated by two of the greats. Nice!— Donald J. Trump (@realDonaldTrump) July 3, 2019
The National Park Service (NPS) is diverting a portion of entrance and recreation fees intended to improve parks across the US in order to foot the bill for the parade, reports the Washington Post.
In previous years, the 4 July celebration on the National Mall has typically cost the agency about $2m, according to the newspaper.
The diverted funds are just a small fraction of the National Park Service's $2bn plus budget.
But the agency complained in March that it is facing almost $12bn in backlogged maintenance and repair needs - exacerbated by the US government shutdown at the beginning of this year.
In a statement, the NPS confirmed that "costs will increase this year" due to the display and Mr Trump's presence.
"Any time a president visits a public place like a national park to address the American public there are necessary additional costs associated with public safety and security," they said in a statement, declaring that the event will take place "rain or shine".
"In this case those costs will be shared by the White House, the National Park Service, US Park Police, Secret Service and other law enforcement partners based on areas of responsibility."
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's the reaction?
Mr Trump's Independence Day plans have divided opinion.
Critics of the president see it as an inappropriately partisan display and a misuse of public funds.
Hawaii Senator Brian Schatz decried the event and "enormous waste of resources" on Twitter.
Kids in cages. Tanks on the streets. Friendships with dictators. Fights with democracies. VIP access for donors at a July 4 event. Attacking the press. There is nothing patriotic about any of that.— Brian Schatz (@brianschatz) July 2, 2019
"Tanks on the streets...VIP access for donors at a July 4 event," the Democrat wrote. "There is nothing patriotic about any of that."
The National Park Service has issued a permit to feminist group Code Pink to stage a demonstration in the vicinity of the event.
Tanks but no tanks, say DC residents to Trump pic.twitter.com/EYROUUGrGk— Medea Benjamin (@medeabenjamin) July 3, 2019
They plan to display an inflatable balloon depicting Mr Trump as a baby to protest against the "militarisation" of the US holiday.
But organisers were denied permission to use helium for the balloon to make it airborne.