Story highlights Kerry is a veteran of the Vietnam War

He met a former enemy on Saturday, decades after they fought on opposite sides, and they shook hands

(CNN) Secretary of State John Kerry visited on Saturday the very site where he killed a Vietnamese soldier in battle almost 50 years earlier, when his Swift Boat was attacked by the Viet Cong.

Kerry was a young US Navy officer at the time, in his mid-twenties, and the battle in the Mekong river earned him a Silver Star.

In his fourth visit to Vietnam as secretary of state, Kerry met with Vo Ban Tam, a 70-year-old veteran who was part of a team that ambushed the secretary's Swift Boat in 1969. Through an interpreter, Ban Tam explained that he knew the man Kerry killed, it was his 24-year-old friend and fellow soldier, Ba Thanh.

Kerry and Ban Tam shook hands, and Kerry presented one of his commemorative Challenge Coins to Ban Tam.

Kerry shakes hands with Vo Van Tam.

"Today I met Vo Ban Tam, a former VC enemy who farms shrimp and crab on the same #Mekong river we once fought over," Kerry tweeted, expressing how powerful it is that veterans from both sides can now get together and work on strengthening U.S. -- Vietnam relations.

Today I met Vo Ban Tam, a former VC enemy who farms shrimp and crab on the same #Mekong river we once fought over. pic.twitter.com/O1h4RxpwS6 — John Kerry (@JohnKerry) January 14, 2017

Very powerful that veterans from both sides of the war can now be friends & work towards same goal of strengthening U.S.-#Vietnam relations. pic.twitter.com/V4jiKXZuef — John Kerry (@JohnKerry) January 14, 2017

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