UPDATE 1-Siemens sets ultimatum for ex-execs in bribe case

* Says the 7 must declare intention to settle by mid-Nov

* Threatens to take legal action if deadline not met (Adds background, comment)

FRANKFURT, Sept 23 (Reuters) - Germany's Siemens (SIEGn.DE) on Wednesday threatened to sue seven former executives if they fail by mid-November to agree to pay part of the multi-billion-euro costs of a massive corruption case.

The offer applies to former Chief Executive Klaus Kleinfeld, supervisory board chairman Heinrich von Pierer as well as ex-board members Johannes Feldmayer, Thomas Ganswindt, Heinz-Joachim Neubuerger, Juergen Radomski and Uriel Sharef, Siemens said in a statement.

Siemens agreed last December to pay more than $1.3 billion to settle corruption probes in the United States and Germany, ending two years of controversy that rocked the German engineering conglomerate.

The company believes the whole case cost it 2-3 billion euros, including legal fees and payments to the U.S. and German governments.

The U.S. authorities said Siemens made almost $1.8 billion in improper payments to government officials and third parties from March 2001 through 2007 in elaborate schemes involving employees at all levels. [ID:nN15508680]

The company previously said it wanted to claim damages from 11 former top managers including von Pierer and Kleinfeld for failing to stop illegal practices and bribery at Siemens.

Von Pierer and Kleinfeld resigned in 2007. They were not accused of crimes and both denied any wrongdoing.

Sueddeutsche Zeitung daily, citing supervisory board sources, reported on Wednesday that Siemens would take von Pierer to court to reclaim costs from the case.

A Siemens spokesman declined comment on the report.

A company source told Reuters the amounts that can be reclaimed from those who refuse to settle will depend on their personal assets.

To be able to claim for damages, the company would have to prove that the corruption case cost it 2-3 billion euros, the source said. (Editing by David Cowell)