Bill Clinton: "a bad mistake"

Mr Clinton said sorry during a photocall with Irish Prime Minister Bertie Ahern at Dublin Castle.

He reacted to remarks by Connecticut Democratic Senator Joseph Lieberman, who on Thursday said Mr Clinton has been "immoral".

The president, on day two of a three-day visit to Northern Ireland and the Irish Republic, said: "I can't disagree with anyone else who wants to be critical of what I have already acknowledged was indefensible.

"I've already said I made a bad mistake and it was indefensible and I'm sorry."

President Clinton had just arrived for his talks with the Irish Prime Minister in Dublin when the subject of Senator Lieberman's devastating criticism of him was raised by reporters.

Looking highly embarrassed, Mr Clinton said he had been briefed on what had been said in the senate and added that he basically agreed with it.

BBC's Gavin Esler: "very interesting development".

It is the first time Mr Clinton has publicly apologised over his affair, which started when Miss Lewinsky was a 21-year-old unpaid White House worker.

Usual rules suspended

It is unusual for an American president to be subjected to domestic political criticism while on a foreign trip.

Joseph Lieberman: president is a role model

Senator Lieberman, a long-time ally of the president, said he felt angry and disappointed over the Lewinsky scandal.

"It sends a message of what it acceptable behaviour to the larger American family, particularly to our children, " he said.

He stopped short of demanding the president's resignation, but BBC Washington correspondent Paul Reynolds says his comments could blaze a trail for other Democrats and make it acceptable to say in public what many of them think in private.