Image copyright Ashburn Old School Rehabilitation / Facebook

A historic black school in Virginia which was being restored has been vandalised with racist graffiti.

The Ashburn Colored School in Virginia, about 30 miles (50km) west of Washington DC, was discovered covered in swastikas and "white power" slogans.

Local students had been restoring the crumbling building, hoping to create an education museum.

The group, which had raised $20,000 (£15,000) for the project, said it was "heartbroken about this senseless act".

Loudoun County Sheriff's Office has opened an investigation.

"The vandalism to the Old Ashburn School is reprehensible and will not be tolerated here in Loudoun County," said Sheriff Mike Chapman.

Image copyright Ashburn Old School Rehabilitation / Facebook Image caption The original windows had recently been restored

The Ashburn Colored School opened in 1892, when schools were racially segregated by law, to teach African American students in Loudoun County.

It remained open until the late 1950s, years after the US Supreme Court banned segregated education.

Former student Yvonne Neal said: "It's like a landmark for those of us who went there."

Students from the neighbouring Loudoun School for the Gifted, who have been working on the restoration, hope to transform the interior into a museum of education.

"While we are heartbroken about this senseless act, please know that our students, volunteers, and community will work even harder to complete the dream of renovating the Ashburn Colored School," the group said on its Facebook page.

A crowdfunding campaign for the project raised over $21,000, with a fresh wave of donations arriving since the vandalism.

The organisers estimate the total cost of the project at close to $100,000.