VICKSBURG, Miss. — Authorities said Thursday they fear dozens of veterans could lie in unmarked graves at a Mississippi military cemetery after they found two unidentified coffins and used radar to detect other possible plots.

The two coffins and other potential graves were found in sections of Vicksburg National Military Cemetery that were opened in the 1940s for World War I, World War II and Korean War veterans, National Park Service officials said at a news conference. The sprawling cemetery is the final resting place for more than 18,000 veterans, mostly Union soldiers from the Civil War.

The problems were discovered after workers preparing a burial site for a World War II veteran found a coffin in August. Another coffin was found nearby. The veteran was buried elsewhere in the cemetery and the graves were left alone, authorities said.

The cemetery stopped offering burials in 1961, except for veterans who had prior arrangements. There have been 109 burials since then.

The park service asked for help from the Army Corps of Engineers, which used ground-penetrating radar devices to search for graves. Those sites were then checked by pushing metal rods into the ground, which in several cases hit solid objects that could be coffins.

The National Park Service’s Southeast Archaeological Center has also been helping. Officials said a preliminary analysis of their research identified “eight probable and 48 possible unmarked graves.”

Vicksburg National Military Park Superintendent Michael Madell said officials haven’t found any documentation to help identify the unmarked graves, despite searching cemetery records, archives and looking for lost documents.

Madell said federal authorities are trying to respect the dead by using research methods that don’t physically disturb the graves, like the radar devices.

The park service is confident it will be able to determine how many of the sites are indeed graves by using the minimally intrusive detection methods, searching archives around the country and contacting veterans groups, said spokesman Bill Reynolds.

TAMPA, Fla. — Standing before a packed hall of 700 military doctors and medics here, the deputy commander of the nation’s elite special operations forces warned about an epidemic of chronic pain sweeping through the U.S. military after a decade of continuous war.

Be careful about handing out narcotic pain relievers, Lt. Gen. David Fridovich told the audience last month. “What we don’t want is that next generation of veterans coming out with some bad habits.”

What Fridovich didn’t say was that he was talking as much about himself as anyone.

For nearly five years, the Green Beret general quietly has been hooked on narcotics he has taken for chronic pain — a reflection of an addiction problem that is spreading across the military. Hospitalizations and diagnoses for substance abuse doubled among members of U.S. forces in recent years. This week, nurses and case managers at Army wounded care units reported that one in three of their patients are addicted or dependent on drugs.

In going public about his drug dependency during interviews, Fridovich, 59, echoes the findings of an Army surgeon general task force last year that said doctors too often rely on handing out addictive narcotics to quell pain.

An internal Army investigation report released Tuesday revealed that 25 percent to 35 percent of about 10,000 soldiers assigned to special units for the wounded, ill or injured are addicted or dependent on drugs, according to their nurses and case managers. Doctors in those care units told investigators they need training in other ways to manage pain besides only using narcotics.

“I was amazed at how easy it was for me or almost anybody to have access and to get medication, without really an owner’s manual,” says Fridovich, deputy commander of the nation’s roughly 60,000 Green Berets, Army Rangers, Navy SEALs and secretive Delta Force teams.

For such a high-ranking military officer, publicly acknowledging drug dependency was unprecedented.

Retired Army Maj. Gen. Paul Eaton, a former commander in Iraq, says Fridovich has now joined a small cadre of senior military leaders willing to discuss publicly personal struggles, such as living with post-traumatic stress disorder. Such admissions are difficult professional decisions, Eaton says.

“Nobody wants to show weaknesses. You want to be perceived as perfection,” he says. “But sometimes moral courage kicks in where moral courage is demanded.”