* U.S. govt suspects bribery in China, India -filings
* Alstom one of biggest fallers in pan-European index
* Company is cooperating with U.S. authorities
* Says too early to speculate on potential settlement (Adds Alstom lawyer comment)
By Natalie Huet and Aruna Viswanatha
PARIS/WASHINGTON, March 27 (Reuters) - Alstom shares fell sharply on investors' fears that the French engineering firm could face a heavy fine from the U.S. Justice Department as a result of a bribery investigation that has spread across Asia.
Alstom is cooperating with the investigation and it is premature to speculate on its findings or how big any possible settlement could be, a company spokeswoman said on Thursday.
A spokesman for the Justice Department (DOJ) declined to comment.
Shares in Alstom closed 4.9 percent lower on Thursday, one of the biggest losers in the pan-European FTSEurofirst 300 index .
According to court filings seen by Reuters and first reported by Bloomberg earlier on Thursday, the Justice Department has evidence that a former Alstom executive tried to bribe officials to secure power projects in Indonesia, India and China.
Two executives of Alstom's U.S. subsidiary in Connecticut have already pleaded guilty and admitted to paying bribes on behalf of the company in connection with a project on the Indonesian island of Sumatra.
The long-running investigation could result in penalties of several hundred millions of dollars, legal experts say.
Alstom's bigger rival Siemens agreed to pay $800 million to the U.S. Justice Department in 2008 to settle a global bribery scandal.
The risk of a heavy fine from the United States spells more bad news for the company, whose shares have slumped over 40 percent in the past 12 months on concerns over its cash flow.
Hit by a drop in orders for power equipment, Alstom 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.
The U.S. probe into Alstom initially focused on a $118 million contract to provide services at a power plant in Sumatra. The contract, known as the Tarahan project and completed in 2007, was part of a joint venture between Alstom and Japan's Marubeni Corp.
Last week, Marubeni pleaded guilty to paying bribes to win that project and was fined $88 million.
While investigating the Sumatra deal, the Justice Department found evidence of possible bribery in 11 other energy projects in Indonesia, India and China, according to court documents filed in a case against a former manager at Alstom's Connecticut offices.
The court papers filed by the U.S. government cite entertainment expenses and emails from Alstom employees referring to "special attention" and fees to be paid to local officials to help secure contracts.
A lawyer for Alstom in the U.S. said the company was cooperating "closely, actively, and in good faith" with the U.S. investigation.
"In the course of our regular consultations, the DOJ has not identified any on-going shortcomings with the scope, level, or sincerity of the company's effort," the lawyer, Robert Luskin, said in a statement.
"The discussions with the DOJ have not evolved to the point of negotiating a potential resolution of any claims. Any effort to estimate the size of any possible fine is sheer speculation, as would be any comparison with other cases that have recently been resolved."
Penalties in such cases are usually based on the profits the company allegedly obtained through its conduct. They can rise substantially from that if the conduct is widespread across the company, if senior management sanctioned it, and if the company did not fully cooperate in the investigation. (Editing by Erica Billingham and Keiron Henderson)