(Reuters) - General Electric Co
GE said it agreed to the extension to facilitate discussions with the French government. GE has encountered resistance from the French government, which has sought to encourage Germany's Siemens
"We view this extension positively," GE said in a statement.
In a separate statement, Alstom said: "Alstom welcomes GE's initiative to extend the period review of the offer by Alstom's board in order to allow the constructive dialogue with the French state to continue."
Representatives at the French government could not immediately be reached for comment.
GE Chief Executive Jeff Immelt told an investor conference on Wednesday that the company was still going to "work constructively" with the French government on its bid and that he expects the deal to close.
"We wouldn't have started if we didn't think we could finish," Immelt said at the conference.
A source familiar with the talks said Immelt was aware that an extension was likely when he made his comments on Wednesday.
GE last month made its offer for Alstom's power turbine and grid arm in a deal designed to expand its installed base of power turbines, get a more complete offering to power customers and broaden GE's presence in emerging markets.
French Economy Minister Arnaud Montebourg said earlier on Thursday that the government was studying an all-French solution for Alstom that could involve public funds.
"Plan A is GE, plan B is Siemens, plan C is a home-based solution," Montebourg said.
Under pressure from the French government, Alstom has also opened its books to Siemens, which has dangled its rail business as part of a possible asset swap. Siemens has asked Alstom for more information ahead of any offer for the power business.
(Reporting by Lewis Krauskopf, additional reporting by Maya Nikolaeva in Paris; Editing by Chris Reese and Cynthia Osterman)