(Corrects paragraph 6 reference to "rail arm" from "power arm")
* Alstom shares up more than 14 percent
* Alstom says not informed of any offer
* Alstom was bailed out by French state in 2004
* GE may only want to own power assets-person familiar with the industry
By Natalie Huet and Benjamin Mallet
PARIS, April 24 Shares of Alstom jumped more than 14 percent on Thursday after a report that U.S. conglomerate General Electric was in talks to buy the struggling French turbine and train maker for about $13 billion.
The companies may announce the deal as early as next week, Bloomberg cited people with knowledge of the matter as saying late on Wednesday.
If confirmed, a takeover offer from a foreign company would raise concern among politicians and unions in France, where Alstom employs around 18,000 staff, or 20 percent of its global workforce.
The group was bailed out by the French state a decade ago and has strongly relied on orders from national rail operator SNCF and utility EDF.
A deal could hand GE control of Alstom's high-speed TGV trains and rail-signal technology, and has the support of Bouygues, Alstom's biggest shareholder with a 29 percent stake, the report said.
However, one person familiar with the industry said GE's ultimate aim might be to buy Alstom's power business rather than its rail arm - a deal that would leave its transport business as a separate publicly listed company in Paris. A report in the French Le Figaro newspaper also said the power division was GE's main target.
GE has said it wants to increase the earnings contribution of its core industrial manufacturing business to 70 percent from 55. Acquiring Alstom could cement its leadership as a provider of large infrastructure equipment to customers around the world.
"Alstom is levered to those themes in which GE believes," Sanford Bernstein analyst Steve Winoker said in a research note. "GE would essentially be 'doubling down' on power generation, transmission, distribution and transportation."
Alstom, which has put its transport division up for sale in an attempt to fill a hole in its balance sheet, said on Thursday it was "not informed of any potential public tender offer for the shares of the company" and promised an update on its options when it releases annual results on May 7.
Bouygues would not comment beyond saying that it supported Alstom's strategy. A GE spokesman declined to comment.
Before the takeover bid report, Alstom shares had slumped 20 percent in the past 12 months on concerns over its cash flow. Those concerns prompted Bouygues to take a $1.9 billion writedown on its Alstom stake in February.
Analysts at Espirito Santo investment bank said that at an enterprise value to forecast 2015 EBITDA multiple of 9.6 and a premium of 27 percent to Wednesday's close, the reported price GE was offering still represented a 14 percent discount to the rest of the European capital goods sector.
Alstom shares leaped in early trade and closed up 10.9 percent at 27 euros compared with the potential offer price that works out around 30.5 euros per share.
Alstom has been hit hard by Europe's economic weakness and a drop in orders for power equipment from utilities, which in turn are suffering from low electricity prices. Its train business has held up better and secured record orders.
The group announced 1,300 job cuts last year and put assets up for sale to raise cash, including a stake in its transport business, which makes France's prized high-speed TGV trains. . An IPO of the business is also a possibility.
Analysts see sense in a tie-up. GE has the cash Alstom needs and a deal could help the U.S. group get infrastructure assets cheaply and make cost savings in power generation. For instance, GE is looking to expand in smart grid technology, where Alstom is a strong player.
A deal would also help Alstom strengthen its finances as it faces an investigation by the U.S. Justice Department for alleged bribery and could face a heavy fine.
"GE is a big company with big cash flow. Alstom is under greater pressure than the market appreciates, especially due to the DoJ investigation," said Nomura analyst Daniel Cunliffe.
French Prime Minister Manuel Valls told reporters the government would keep a close watch on jobs, technology and decision-making. His economy minister, Arnaud Montebourg, has a track record of intervening in big industrial deals.
(Additional reporting by Alexandre Boksenbaum-Granier, Matthieu Protard and Jean-Baptiste Vey in Paris, Pamela Barbaglia and Anjuli Davies in London, Lewis Krauskopf in New York, Aman Shah in Bangalore; Writing by Natalie Huet and Andrew Callus; Editing by Erica Billingham and Elaine Hardcastle)