Stephen Bosworth, a veteran U.S. diplomat who for many years headed Washington's engagement with North Korea, has died. He was 76.

Bosworth served as ambassador to South Korea from 1997 until 2001. In 2009 he was named special representative for North Korean policy, a position in which he was "tireless" in his work, U.S. Secretary of State John Kerry said in a statement Tuesday.

Bosworth advocated engagement with North Korea but was quoted as saying privately he doubted South Korean President Kim Dae-jung's Sunshine Policy toward Pyongyang would reap rewards.