Siemens and France weigh in as GE eyes Alstom deal

* French minister confirms GE wants to buy Alstom power arm

* Siemens ready to discuss "future strategic opportunities"

* President Hollande gathers ministers to discuss Alstom

* Minister says Siemens deal would create "champions"

* Alstom seeks shares suspension until Wednesday (Adds detail on government meeting, Immelt visit, Alstom statement, context)

By Benjamin Mallet and Maria Sheahan

PARIS/FRANKFURT, April 27 (Reuters) - Siemens and the French government intervened in General Electric's plan to buy the power arm of Alstom on Sunday with an alternative European "champions" tie-up proposal and a pledge to act in France's national interest.

Though French trains-to-turbines maker Alstom is privately owned, firebrand Economy Minister Arnaud Montebourg issued a stark reminder of the influence the government holds over a company that relies heavily on orders from state rail operator SNCF and partly state-owned utility EDF.

"GE and Alstom have their calendar, which is that of shareholders, but the French government has its own, which is that of economic sovereignty," Montebourg said in a statement, providing the first official confirmation of GE's offer.

GE boss Jeff Immelt was in Paris on Sunday to thrash out a $13 billion deal for struggling Alstom's power turbines and grid equipment. Montebourg had planned to meet him but the encounter was postponed until later in the week after the minister advertised an alternative proposal by German rival Siemens.

The Siemens proposal would create "two European and global champions in the energy and transport domains - one around Siemens, the other around Alstom", Montebourg said.

French President Francois Hollande gathered his top ministers on Sunday evening to discuss Alstom's case. The company said separately it would make an announcement no later than Wednesday morning and that it had asked for its shares to remain suspended from trading until then.

"Alstom continues and deepens its strategic reflection," it said in a three-line statement.

Montebourg said the government would not accept any hastily made decision, that it would seek to preserve France's jobs and industrial base and would in particular be "extremely vigilant" in ensuring the nation's nuclear industry remains independent.

The warning compels Alstom and GE to tread carefully. However, sources familiar with the talks said these were very advanced.

"Alstom has received a firm offer from GE and an expression of interest from Siemens. It's not at all the same kind of commitment," one of the sources said.

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