South Korean President Roh Moo-hyun's political clout took another hit Tuesday, when he vetoed the appointment of an independent prosecutor to investigate scandals involving several his aides.

President Roh Moo-hyun on Tuesday blocked opposition legislators from appointing a special counsel to probe corruption allegations involving three presidential aides. The move outraged the opposition and is likely to increase tensions between Mr. Roh and his political rivals.

Mr. Roh told parliament Tuesday that as the president of South Korea, he wants to send the resolution back for review. He says his administration will offer a new bill on same the issue, which the National Assembly and people of South Korea can judge.

His opponents, who are spread among three parties and hold a majority in parliament, pledged to fight him, but it is unclear whether or not they will seek to overturn his veto in parliament.

The sponsor of the bill, the main opposition Grand National Party, vowed to wage an "all-out struggle" and said it would start by boycotting an upcoming debate on next year's budget.

The dispute represents another blow to the Roh Presidency, which has weakened as the public has withdrawn its trust. Mr. Roh, who took office nearly one year ago, recently called a public confidence vote for December, saying he needs the public's endorsement to govern and would leave office if he lost. But it is unclear if the referendum will be held, since there is no precedent for such a vote in South Korea.

Corruption scandals involving at least three high-level aides have battered Mr. Roh's credibility, especially since the former labor lawyer promised to stop such practices, long a part of South Korea's politics.

Also damaging public confidence in South Korea's leadership: Prosecutors probing political fundraising during last year's presidential campaign on Monday raided an office of the country's largest conglomerate, Samsung Group. Another corporate giant, LG Group, is also under investigation.

The Seoul district prosecutor's office has confirmed that Monday's raid was part of a probe into alleged shady ties between the country's powerful family-run companies and politicians and bureaucrats.