Racist graffiti was painted in the parking lot of a Tennessee social justice centre that hosted giants of the 1960s US civil rights movement, such as Martin Luther King Jr. and Rosa Parks, it said on Tuesday.

The Highland Research and Education Centre, whose main office burned down last week, was home to innumerable documents, recorded speeches and artefacts from the movement that were lost in the fire, it said on its website.

It described the graffiti only as a “white power” symbol painted on the parking lot.

“While we do not know the names of the culprits, we know that the white power movement has been increasing and consolidating power across the south,” the centre said in a statement on Tuesday. “Now is the time to be vigilant.”

Friday’s fire was less than a week after another fire police say was race-driven arson at a Southern California mosque, where racist graffiti was left in the parking lot.

Charlottesville one year on Show all 15 1 /15 Charlottesville one year on Charlottesville one year on Mary Grace, from Durham, North Carolina, walks through the downtown mall area August 11, 2018 in Charlottesville, Virginia. Charlottesville has been declared in a state of emergency by Virginia Gov. Ralph Northam as the city braces for the one year anniversary of the deadly clash between white supremacist forces and counter protesters over the potential removal of Confederate statues of Robert E. Lee and Jackson. A "Unite the Right" rally featuring some of the same groups is planned for tomorrow in Washington, DC. Getty Charlottesville one year on Chris Jessee (R) hands out placards to people visiting downtown Charlottesville as the city marks the anniversary of last year's 'Unite the Right rally' in Charlottesville, Virginia, USA, 11 August 2018. On 12 August 2017, a bloody clash between white supremacists and counterprotestors in Charlottesville left three people dead and dozens injured Getty Charlottesville one year on A member of the Virginia State Police waits outside the park where a statue of Confederate Gen. Robert E. Lee is located August 11, 2018 in Charlottesville, Virginia. Charlottesville has been declared in a state of emergency by Virginia Gov. Ralph Northam as the city braces for the one year anniversary of a deadly clash between white supremacist forces and counter protesters over the potential removal of Confederate statues of Robert E. Lee and Jackson. A "Unite the Right" rally featuring some of the same groups is planned for tomorrow in Washington, DC Reuters Charlottesville one year on A woman displays a shirt ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. Reuters Charlottesville one year on A sign reading "Strength, which was taken down at the request of police officers, hangs by the statue of Civil War Confederate General Robert E. Lee, ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. Reuters Charlottesville one year on Law enforcement arrives ahead of the one year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018 Reuters Charlottesville one year on A vendor displays wares on the mall as State Police lock down the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., Saturday, Aug. 11, 2018. The Governor has declared a state of emergency in Charlottesville AP Charlottesville one year on A Police bike patrol takes a break in the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., Saturday, Aug. 11, 2018. State and local authorities framed the weekend's heightened security as a necessary precaution. AP Charlottesville one year on State Police arrest a local resident, John Miska, in the locked down downtown area in Charlottesville, Va., Saturday, Aug. 11, 2018. Miska purchased razor blades, which are banned items, in a downtown drugstore. On the the anniversary of white supremacist violence, state and local authorities framed the weekend's heightened security as a necessary precaution. AP Charlottesville one year on State Police escort local resident, John Miska, red hat, after he was arrested in the locked down downtown area in Charlottesville, Va., Saturday, Aug. 11, 2018. Miska purchased razor blades, which are banned items, in a downtown drugstore. On the the anniversary of white supremacist violence, state and local authorities framed the weekend's heightened security as a necessary precaution. AP Charlottesville one year on A group Anti-fascism demonstrators, march in the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., Saturday, AP Charlottesville one year on A group anti-fascism demonstrators march in the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., AP Charlottesville one year on People receive first-aid after a car accident ran into a crowd of protesters in Charlottesville, VA on August 12, 2017. A vehicle plowed into a crowd of people Saturday at a Virginia rally where violence erupted between white nationalist demonstrators and counter-protesters, witnesses said, causing an unclear number of injuries AFP/Getty Charlottesville one year on Alt-right rally members in Lee Park in Charlottesville, VA on Saturday August 12, 2017 White nationalist 'Unite the Right' rally, Charlottesville, USA Rex Charlottesville one year on A counter protester who got hit with a stick by alt-right member covered with blood on his face in Lee Park in Charlottesville, Rex

No one was injured in either fire.

The Jefferson county sheriff’s office is investigating the Highland Centre fire as a possible crime, broadcaster NBC and other media have said.

A sheriff’s spokesperson was not immediately available to comment to Reuters early on Wednesday.

Republican Gov. Kevin Stitt called the incident “abhorrent”, media said.

The Highland Centre helped organise the Montgomery, Alabama bus boycotts of 1955 that were among the first major civil rights protests of the movement in the United States.

Protesters, mostly black residents, refused to ride city buses in a bid to defy racial segregation, after Parks was arrested for refusing to give up her seat to a white person.

The centre also helped found the Student Nonviolent Coordinating Committee, a youth movement that worked with Martin Luther King Jr.’s efforts to ensure voting rights and social justice for minorities, it said on its website.