DALLAS (AP) _ The John F. Kennedy Memorial was defaced by vandals with spray paint who caused thousands of dollars worth of damage.

The black and red graffiti on the interior walls of the downtown memorial might have been done by a hate group, said Officer Leroy Quigg of the Dallas police gang unit. The painted images included a swastika.

Police believe the vandalism occurred late Friday night or Saturday morning. Cleanup should be completed in a few days, officials said.

The monument attracts about 500,000 visitors annually. It was also vandalized in 1997.

The memorial, built in 1970, consists of 50-foot-high white concrete walls that surround a square black marble slab bearing the name of the president who was assassinated nearby in 1963.