Ruling party candidate Roh Moo-hyun won South Korea's presidential election on Thursday, a result which could complicate ties with the United States as the allies grapple with North Korea's nuclear programme.
The official count of ballots showed Roh beat conservative opposition candidate Lee Hoi-chang by 2.3 percentage points in a closely fought election which had become a referendum on how to handle South Korea's unpredictable communist neighbor.
Roh thanked his supporters and vowed to work for every South Korean "not just those of you who backed me."
Roh will have little time to savor his victory, facing a hostile parliament controlled by Lee's party, a slowing economy and the Bush administration's starkly different approach toward North Korea - which it branded part of an "axis of evil" with Iraq and Iran - and its nuclear arms.
The voter turnout of 70.2 per cent was the lowest in South Korean history.
"I have failed again in my bid for the presidency," said Lee, who lost the 1997 election to incumbent President Kim Dae-jung.
The triumph of Roh, 56, a populist human rights and labor lawyer, marks a stunning turnaround after the 11th-hour desertion of his election alliance partner, Chung Mong-joon.
Roh has vowed to be tough on the family-run conglomerates dominating Asia's fourth-largest economy, but continue Kim's "sunshine policy" of reconciliation with North Korea.