(Adds additional quotes)

WASHINGTON, May 9 (Reuters) - Venezuelan President Hugo Chavez's ties to Colombian rebels are deeper than previously thought, U.S. officials said on Friday, following an analysis of files on a dead guerrilla leader's laptops.

The files appear to be authentic and underscore U.S. concerns about Chavez's quest for more influence in the region, an intelligence official said. Their discovery in March raised speculation the United States would put Venezuela on its list of state sponsors of terrorism.

"It (the analysis) reinforces the U.S. government's strong position that Chavez is attempting in various ways to project his influence throughout the region and that influence in some ways could be construed as destabilizing," the intelligence official said.

Another U.S. official, who spoke on condition of anonymity because the issue involves classified information, described the files as a huge public relations win for Colombia, which is battling the guerrillas of the leftist Revolutionary Armed Forces of Colombia, or FARC.

"The involvement does seem to extend fairly high up in the Venezuelan government. This isn't a bunch of local yokels on the border doing their own thing," the official said.

Chavez contends the Colombian government faked the files.

Although Chavez's sympathies for the FARC are well known, Colombia has said the files seized in a March attack show Chavez offered financial support to the group.

The Wall Street Journal reported on Friday that the files also indicate Venezuela offered to arm the rebel group, possibly with rocket-propelled grenades and ground-to-air missiles. It said Venezuela offered FARC the use of a port to receive arms shipments.

The files document discussions between the rebels and Chavez about closer ties and portray a "deeper relationship than previously known," the intelligence official said.

The March attack by Colombia on a rebel camp in Ecuador killed a senior FARC leader and inflamed regional tensions. That and other recent attacks are seen as having weakened the rebel group that has been fighting a four-decade civil war in Colombia, to the point where FARC is "on its heels," the intelligence official said.

"However, they have shown an ability in the past to regroup and to regenerate leadership."

Bernardo Alvarez, Venezuela's ambassador to the United States, told the Journal in an interview on Wednesday, that the computer files were "false and an attempt to discredit the Venezuelan government."

The files indicate Venezuela has raised the prospect of drawing up a joint security plan with FARC and has sought basic training in guerrilla-warfare techniques, the Journal said, suggesting Chavez was preparing for a possible U.S. invasion of Venezuela.

(Reporting by Randall Mikkelsen at Guantanamo Bay U.S. Naval Base, Cuba, and David Morgan in Washington; Editing by Eric Beech)

AlertNet news is provided by