The head of a foundation set up to oversee debt-laden Berlin's three opera houses is to step down, the city government said Wednesday, amid tensions with the capital's mayor.

Michael Schindhelm was appointed in late 2004 as the first general director of the foundation, created in an effort to enhance coordination, cut costs and keep open all three houses — the Staatsoper, Deutsche Oper and Komische Oper.

Mayor Klaus Wowereit described Schindhelm's decision to go as "a personal decision" and did not elaborate on his reasons for quitting.

However, Schindhelm, a former director of Switzerland's Basel Theater, has had an uneasy relationship with Wowereit. The center-left mayor won a new five-year term in September and now plans to take direct responsibility for cultural issues.

The city government said that Schindhelm agreed to stay until April 1, rather than departing immediately, and help develop plans for the future.

Funding for the arts and other projects in Berlin has been a problem since German reunification in 1990 brought together facilities in the east and west, including the three operas, two zoos and three airports. The city has long agonized over how to avoid closing or merging opera houses.

Berlin's financial worries deepened last month when Germany's highest court threw out a city government bid for federal help in tackling debts of US$77 billion.

Wowereit has been pressing for the federal government to take over responsibility for the Staatsoper, led by Daniel Barenboim, on the grounds that it represents the whole country. That, he argues, would allow Berlin to dedicate more funding to the other two houses.

"It is increasingly clear that the creation of the opera foundation so far has not contributed sufficiently to solving the fundamental problems," Wowereit said in a statement Wednesday.

"It is now time to shape calmly and thoroughly the future of the opera landscape," he added. "It is the city government's stated aim to maintain all three opera houses."

The Berliner Zeitung newspaper reported that Schindhelm, in his resignation letter, charged that Wowereit had "called into question the foundation and me personally."

Federal officials have resisted Wowereit's call to take over the Staatsoper saying they already do plenty for culture in the capital. The opera foundation said Wednesday it supports the mayor's argument but also noted that renovation work cannot be delayed.

The federal government has taken over Berlin's Academy of Arts, is funding the US$1.5 billion restoration of the famed Museum Island complex, and says it has spent more than US$3.9 billion on culture in the capital since 1999.

The conservative Christian Democrats, the opposition party in Berlin, called for an "opera summit" of political and cultural leaders to map future strategy.

Wowereit "faces a self-inflicted disaster (with) no workable opera concept," they said in a statement.