Voters stunned the governing party in a national election by stripping it of a parliamentary majority for the first time in South Korea's 40-year history.

President Roh Tae-woo, who took office in February, said the big gains by opposition candidates in Tuesday's National Assembly races would make it difficult for him to govern.Stock prices plunged to record lows after the upset.

Final returns released Weddnesday showed that 164 candidates from three main opposition parties were assured of seats in the 299-member National Assembly. Roh's party won 125 seats, independents captured nine and one race still was undecided. Earlier returns, based in part on projections, had 166 opposition seats and and 123 governing party seats.

The previous National Assembly had 276 seats 160 held by the governing party and 87 by the three main opposition parties.

The election was the first test of public confidence in the Roh government, which in December narrowly won the country's first direct presidential elections in 16 years.

Balloting was marred by violent demonstrations that left at least two people dead. Protesters backing opposition candidates marched in the streets, battled riot police and accused Roh forces of vote tampering. Scores of protesters were detained.

Roh said the election "has left many things for us to think deeply about, but I would humbly accept the outcome and do my best to fulfill my promise to the people."

Roh won the presidency with just 36 percent of the vote when the two main opposition leaders, Kim Dae-jung and Kim Young-sam, ran separately and split the anti-government vote in December.

Both Kims won seats in the National Assembly on Tuesday.

Kim Dae-jung's Party for Peace and Democracy emerged as the strongest opposition force with 70 seats. He said lawmakers should consider releasing all political prisoners and demand a probe into the bloody suppression of the 1980 Kwangju protest, in which 200 people died.