SINGAPORE >> Forty-five years ago, as the Vietnam war raged on, Army Spc. Chuck Hagel and Nguyen Tan Dung were on opposite sides of combat serving in the Mekong Delta — both wounded more than once as they battled for their countries.

This weekend the two men — now America’s defense secretary and Vietnam’s prime minister — met at a formal dinner at the start of an international security conference here, working to help build America’s growing military partnership with Vietnam.

Hagel’s first trip to Asia as Pentagon chief has been a bit of a walk down memory lane for the former infantry soldier.

While Hagel and Dung knew of each other’s service in Vietnam, they had never met. So when they spoke on the sidelines of the dinner, they had the chance to exchange war stories.

Back in 1968, Hagel was a specialist in the 2nd Battalion of the 47th Infantry Regiment, fighting in the Mekong Delta. Dung, who joined the Viet Cong around 1961 when he would have been about 12, and served as a corpsman, then later led a surgery unit reportedly operating in the Delta’s U Minh forest.

According to defense officials, the two men talked briefly about their time at war and the fact that both had bled for their countries. Hung invited Hagel to visit Vietnam, and the secretary said he looks forward to going, said the officials, who spoke on condition of anonymity because they were not authorized to publicly discuss the private meeting.

Hagel also recalled family war history during a private meeting Saturday with Philippines Secretary of National Defense Voltaire Gazmin. According to defense officials, Hagel noted that his father served in that country during WWII with the 13th Army Air Corps. Officials said Hagel told Gazmin that during a visit to the Philippines in the 1980s, he was surprised to see a photo of his father in a foxhole on display in an exhibit — the same photo that had hung in the Hagel family home.

The secretary’s first stop on this Asia trip was in Hawaii, where he recalled going on leave with his brother Tom during the middle of their Vietnam war tour. Hagel ate at the same — although updated — restaurant in Honolulu during this trip as he had back in July 1968, when he and Tom got together at the Halekulani Hotel with their mother and other family members for the weeklong R&R.

To secure the memory, Hagel stood for a photo at the same large tree that his family had posed in front of during that reunion.