Donald Trump has claimed vandals are responsible for issues with the Reflecting Pool in Washington DC following a refurbishment costing more than $14m (£10.5m).
On Saturday, the US president said there had been "multiple arrests" of people who he said had vandalised the "magnificent" pool on the National Mall.
He failed, however, to provide further details to substantiate his claim.
The president launched his renovation project for the pool to mark America's 250th anniversary, as he said his predecessors had let it turn an algae-stained green.
Mr Trump said the pool would go from being in "terrible shape" to looking "gorgeous" thanks to the revamp.
But a few days after the new version, for which an "American-flag blue" was chosen, was unveiled earlier this month, the pool turned a murky green again.
Workers treated it with chemicals to kill the algae, but then the painted blue lining on the bottom began to peel.
"We've had some real problems with vandalism at the beautiful Reflecting Pool," President Trump posted on his social media site on Friday night.
"Just like three days ago, they destroyed the grass outside of the pool, they've also done everything possible to hurt the inside surface that was just installed."
As he made his claim about the arrests on Saturday, he added: "Who would do such a thing?
"These are very serious crimes having to do with the destruction of National Monuments. Years in jail!"
Mr Trump acknowledged in a post that the Reflecting Pool will need to be repaired, yet again, to restore it to "an equal level of beauty" as before.
"We met with contractors today, will probably be forced to release and drain much of the water in order to do the necessary repairs, but will have them done as quickly as possible," he wrote.
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One man arrested was David Hearn, 67, of Bethesda, Maryland, who owned a company that made composite used to build watercraft.
He said he stopped by the pool during his 64-mile bike ride on Friday to see what was going on.
Mr Hearn, a former Olympic canoe racer, told the Associated Press he reached into the pool because he wanted to examine the peeling new coating.
He said he briefly touched a chunk that was still attached to the side of the pool, then let go shortly after a park worker told him to.
But, Mr Hearn said, he was then detained by National Guard troops and Park Police for five hours before being released on Friday night.
"I'm a curious citizen," Mr Hearn said in a telephone interview. "I reached down to see what it felt like. It was very rubbery."
The Washington Post first reported Mr Hearn's arrest, and he said he has a date to appear in court next month and is looking for legal help.
(c) Sky News 2026: 'Vandals arrested' as Trump's $14m reflective pool project sees it turn green again
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