South Korean two main opposition parties edged closer on Monday to trying to impeach President Roh Moo-hyun, but he dismissed the attempt to unseat him for breaking an election rule as an excessive gesture he had a duty to resist.
The National Election Commission said last week Roh had violated election law by speaking in favour of the breakaway Uri Party last month ahead of an April 15 parliamentary election, but did not penalise him.
Impeachment - often threatened but not carried through by opposition parties - would thrust South Korea into uncharted constitutional territory as its economy, Asia's fourth largest, recovers and it grapples with a nuclear crisis in North Korea.
Opposition party officials at the National Assembly told reporters the main opposition Grand National Party had agreed on Monday to join the smaller Millennium Democratic Party to submit an impeachment bill to parliament on Tuesday.