A liner along the bottom of the Lincoln Memorial Reflecting Pool was cut with a sharp knife or razor this month, causing damage to the foam sealant installed as part of a US$16 million rehabilitation project, a top official at the National Park Service says.

The agency reported the June 9 incident to US Park Police, said Frank Lands, deputy director of operations for the park service.

Lands made the statement in a court document filed late on Wednesday as part of a lawsuit filed by a non-profit organisation to halt the Trump administration’s work on the project.

His statement does not say whether the damage is a suspected case of vandalism or identify anyone who might have been involved.

The police report indicates damage to the pool, “including a caulk over the foam sealant that was cut with a sharp knife or razor and destruction of delaminating surface material”, Lands said. About 70 fence post tops also were thrown into the pool, he said.

The statements were the first time the Republican administration has offered specifics for when and how the reflecting pool may have been damaged after work on the project was substantially completed.