(CNN)Members of Congress are calling on federal officials to take down or alter headstones at two national cemeteries that contain swastikas or messages honoring Adolf Hitler.
At Department of Veterans Affairs cemeteries in Texas and Utah, the graves of three German prisoners of war are marked with references to Nazi ideology.
Two graves at Fort Sam Houston National Cemetery in San Antonio depict an iron cross with a swastika at its center, along with an inscription that reads: "He died far from his home for the Führer, people and fatherland." Another grave at Fort Douglas Post Cemetery in Salt Lake City depicts a Knight's cross with oak leaves and a swastika, according to The Salt Lake Tribune.
"Allowing these gravestones with symbols and messages of hatred, racism, intolerance, and genocide is especially offensive to all the veterans who risked, and often lost, their lives defending this country and our way of life," a group of House lawmakers wrote in a letter to Veteran Affairs secretary Robert Wilkie.
"It is also a stain on the hallowed ground where so many veterans and their families are laid to rest. Families who visit their loved ones, who are buried in the same cemeteries with the Nazi soldiers whom they fought against, should never have to confront symbols of hatred that are antithetical to our American values."
The headstones have been standing for decades
The graves have stood in the cemeteries for decades, but were brought to attention in recent weeks after the Military Religious Freedom Foundation (MRFF) called for them to be replaced immediately.
Mikey Weinstein, the founder and president of MRFF, said in a news release that a retired senior military officer alerted his organization to the headstones after he visited the graves of family members at Fort Sam Houston National Cemetery.
"In light of the shocking and inexcusable existence of these Nazi-adorned gravesites in V.A. National Cemeteries, MRFF demands that Secretary Wilkie issue an immediate and heartfelt apology to all United States veterans and their families," Mikey Weinstein, Air Force veteran and founder and president of MRFF, said in a news release.
Weinstein also called on the department to explain why "former enemy military personnel" were allowed to appear in cemeteries maintained by US taxpayer dollars.
Other advocacy groups, including the Southern Poverty Law Center, echoed calls to remove the gravestones.
The Veterans Affairs office has said it is aware of the headstones that contain Nazi-era symbols, which date back to the 1940s and were approved by the US Army.
But the department said it would not remove them because it was obligated by law to preserve historical artifacts.
"The National Historic Preservation Act of 1966 assigns stewardship responsibilities to federal agencies, including VA and Army, to protect historic resources, including those that recognize divisive historical figures or events," the department said in a statement to Salon.com. "For this reason, VA will continue to preserve these headstones, like every past administration has."
CNN has reached out to the Department of Veterans Affairs for comment.