Former German Chancellor Helmut Kohl has resigned as honorary chairman of the opposition Christian Democratic Union (CDU) party after refusing to reveal details of a party funding scandal.

His resignation came in a written statement, shortly after a crisis meeting of his party demanded that he either stand down, or reveal the sources of illegal political donations he failed to declare while in office.

The move is being seen as a humiliating end to the career of the man once regarded as one of the architects of European, as well as of German, unity.

In his statement, Germany's longest-serving chancellor said: "I do not see myself in a position to break my promise to several people who supported my work in the CDU financially.

"The decision ... was not easy."

Mr Kohl, 69, admitted making mistakes but made no mention of resigning from the party or giving up his seat in parliament.

'My political home'

"I have belonged to the Christian Democratic Union for 50 years," said the conservative who held power for 16 years until 1998. "It is and will remain my political home."

Mr Kohl's resignation came after it was announced that Wolfgang Schaeuble would stay on as chairman of the party.

Mr Schaeuble had said the party expected Mr Kohl, who has refused to name the donors of some DM2m ($1m) of funds he accepted on behalf of the party in the 1990s, to either clear up his role in the affair or to face suspension as the party's honorary chairman.

Mr Schaeuble admits that he accepted campaign donations from an arms dealer whose revelations started the affair, and there had been widespread speculation that Mr Schaeuble himself would be forced to step down.

Speaking to reporters after the extended party meeting on Tuesday, Mr Schaeuble said: "The CDU is in the worst crisis in its history."

But he said the party was united behind him and wanted to clear up this growing financial scandal as quickly as possible.

Earlier, the former interior minister Manfred Kanther resigned his seat.

Secret donations

The scandal involves the covering up of secret donations to the CDU and is reaching into all sections of the party.

So far, disclosures have topped DM33m ($17m), including the damaging revelation last Friday by Mr Kanther that the Hesse branch channeled DM13m ($6.8m) in campaign funds through a Swiss account back into Germany when he was state party chairman.

The money was falsely registered as bequests from abroad between 1989-96, some from Jewish donors.

The BBC Berlin correspondent says the public impression is of a party corrupted to the core by 16 years in power.

A criminal investigation has already been launched into the activities of Mr Kohl.

Clean break

Chancellor Gerhard Schroeder has called for a re-run of the Hesse election although Roland Koch, the CDU's regional leader, has insisted he will not resign or call a new election.

But Christian Wulff, another CDU regional leader, said: "We have to make a very radical break and cut ourselves off from all those who are caught up in these scandals."

Mr Kohl's CDU leadership included 16 years in power and Mr Schaeuble was handpicked to succeed him as party leader.

Both men have been summoned before a parliamentary inquiry, which is to hold its first meeting later this week.

The CDU, under Mr Kohl, introduced the party financing law which requires donations exceeding DM20,000 (US$10,000) to be declared.