President Donald Trump is threatening jail time for the alleged vandals he's blaming for damaging the Reflecting Pool on the National Mall in Washington.

It's unclear if the problems with his $16 million renovations are self-inflicted or caused by outside agitators. 

Trump said the only structure vandalized from his sweeping renovation was the Reflecting Pool, which he vowed was being dealt with 'ASAP.'

'It has been given a 300-foot gash, chemicals have been illegally placed in the water, and the beautiful new grass field has been destroyed with '86 47' chemically carved into it,' he wrote on Truth Social Monday morning.

'Please remember that there is a 10 year prison sentence for the destruction, or even the attempted destruction, of such things - which will be fully enforced!'

Trump's threats come as the algae which the project was supposed to remove has dramatically returned, tinting the water green.

Pieces of the newly applied 'American Flag Blue' sealant have appeared to peel up off the bottom of the pool. 

Trump admitted over the weekend that he would 'probably be forced to release and drain much of the water' from the pool to facilitate repairs. 

Trump has repeatedly blamed the problems with the project on nefarious vandals, calling them 'sick, deranged' people on Sunday.

He previously mentioned the alleged 'gash' as being 250 feet long, adding that the US Park Police have arrested people accused of vandalizing the pool.

Trump also commented on the gigantic '86-47' that was apparently branded on the grass of the National Mall recently. 

The Daily Mail has previously reported on the arrest of former Olympian David Hearn, who said he merely touched a piece of sealant. 

Trump has bragged about the success of his project, saying over the weekend that before the vandalism, the pool was 'perfectly' reflective.

Prior to Trump's concession that drainage was likely necessary, workers had vacuumed algae and poured hydrogen peroxide into the water in an attempt to mitigate the pool's problems.