I am sorry for causing troubles to many people

Kim Hong-gul

It is not clear whether he has been formally charged yet. If convicted of bribery, Kim Hong-gul could face up to five years in prison.

Corruption investigations involving government officials as well as two of his sons, have dented President Kim's image.

His second oldest son, Kim Hong-up, is also under suspicion of influence-peddling. He has yet to be questioned by prosecutors.

Apologies

Kim Hong-gul, who has been living in the US for most of the past decade, returned to Seoul for questioning earlier this week.

President Kim's popularity has plummeted

Appearing for questioning on Thursday, he apologised to the country before television cameras and said he had disgraced his parents.

He repeated his apology on Saturday before being taken to jail.

"I am sorry for causing troubles to many people," he said.

Reports say Kim Hong-gul will be held in solitary confinement at Seoul Prison.

The president's son is alleged to have received bribes from lobbyist Choi Kyu-sun to help a lottery operator, Tiger Pools Korea, win a sports lottery licence last year.

History repeats itself

President Kim apologised to the nation for the scandal concerning his sons earlier this month and resigned from his party to concentrate on state affairs.

But the president, who was elected on promises of reform, has seen his popularity plummet.

He is constitutionally barred from seeking a second term in office, but analysts say the series of corruption scandals surrounding his aides, relatives and government officials have damaged the ruling party.

Five years ago the youngest son of former President Kim Young-sam was accused of corruption and influence-peddling.

Kim Hyun-chul was later sentenced to two years in prison on charges of taking $6.6bn in bribes, and evading tax.

That scandal, and the ensuing financial crisis, helped Kim Dae-jung win the 1997 presidential election.