HANOI, Vietnam — Sen. John McCain, who spent five years as a prisoner-of-war in Vietnam, returned Tuesday to visit the infamous "Hanoi Hilton" — this time as a welcome, if somewhat controversial guest.

Vietnam celebrates the 25th anniversary of the end of the Vietnam War on Sunday, and McCain, a Navy pilot shot down on a 1967 bombing run, is the most prominent of the numerous returning U.S. veterans.

"My job here is to commemorate the beginning and continuation of a new relationship between the United States and Vietnam," said McCain, a leading advocate of reconciliation between the former foes.

McCain's arrival at Hanoi's Noi Bai Airport was much more subdued than the red-carpet treatment the Vietnamese provided Monday for a high-profile veterans group, including James Kimsey, founding chief executive officer of America Online.

No senior Vietnamese officials were present, although U.S. Ambassador Pete Peterson welcomed McCain and his wife, Cindy, and teenage son Jack as they came off the plane and into the sweltering heat. A visit to the "Hanoi Hilton," originally planned for Tuesday, was postponed until Wednesday for unspecified reasons.

At a brief airport news conference, McCain was asked if he felt any lingering bitterness from the war. "I put the Vietnam War behind me a long time ago," he said. "I harbor no anger, no rancor."

Shortly after his arrival, McCain attended a solemn airport ceremony in which six sets of remains, believed to be from U.S. servicemen, were placed in silver metal containers, the size and shape of coffins, and put aboard a C-17 cargo plane heading to Hickam Air Force Base in Hawaii for forensic analysis.

About 50 U.S. civilians and military personnel were present for the service, held in silence except for a few clipped military commands. The servicemen saluted, while McCain and the other civilians placed their hands over their hearts as the remains, draped with American flags, were carried into the jaws of the cargo plane.

The remains were recovered this year as part of the ongoing American effort to account for the more than 2,000 servicemen still missing in Indochina, including 1,500 in Vietnam.

The Vietnamese have praised McCain for his role in helping restore diplomatic relations with Washington in 1995, and the senator will meet several of the country's communist leaders. However, his five-day visit has the potential for awkward moments.

During his unsuccessful presidential bid earlier this year, McCain spoke of being tortured by his Vietnamese guards, adding that he and his fellow prisoners referred to their captors with the derogatory term "gooks."

Vietnam denied that the American prisoners were tortured. Some Asian-American groups chastised McCain for his language and urged him to apologize, but he declined.

"John McCain's words and statements, which lack good will, have hurt the Vietnamese and Asian peoples," Vietnam Foreign Ministry spokesman Phan Thuy Thanh said in February at the height of the controversy.

When McCain's plane was downed Oct. 26, 1967, he was fished out of Hanoi's Truc Bach lake by a Vietnamese civilian. He made a 15-minute visit there.

"Everything happened very quickly," McCain said. "I broke both my arms and a leg, and I was dragged ashore, and I was beaten once I was pulled ashore."

His reception was friendly Tuesday. A crowd gathered at the sight of McCain and a throng of media, and several Vietnamese came up to shake his hand and pose for pictures with his family.

McCain was held until March 1973 at Hoa Lo Prison, which the POWs nicknamed the "Hanoi Hilton." He said his hardships included beatings, a lack of proper medical treatment for injuries, and a total of three years in solitary confinement for what his captors called a "bad attitude."

He twice tried to hang himself, using his shirt as a noose, but was caught both times by the guards, who then beat him.

"I couldn't control my despair," McCain wrote in his autobiography. "All my pride was lost, and I doubted I would ever stand up to any man again. Nothing could save me."