A liner along the bottom of the Reflecting Pool in Washington DC was cut with a sharp knife or razor earlier this month, an official at the National Park Service has said.

Frank Lands, deputy director of operations for the park service, said in a court filing on Thursday that US Park Police had responded to a report of an incident on 9 June regarding the pool’s liner, which caused damage to the foam sealant that had been installed as part of a recent multi-million dollar rehabilitation project.

Earlier this week, US President Donald Trump blamed vandals for “a 300 foot long gash” and accused someone of putting fertiliser in the water.

The president was pressed by CBS News during an interview, external for evidence of the slit, which Trump said would be provided in court.

In the recent court filing, Lands said US Park Police report indicated damage “including a caulk over the foam sealant that was cut with a sharp knife or razor and destruction of delaminating surface material.”

It also detailed that “approximately 70 fence post tops were thrown into the pool”.

However, it does not say when exactly the damage occurred and does not identify anyone who might have been involved.

The statement in the court filing is part of a lawsuit filed by a nonprofit organisation seeking to stop the Trump administration’s work on the site.

It is also the first public record detailing how the pool may have been damaged after work on the project was completed.