SACRAMENTO -- California officials said Wednesday they are trying to avert the federal government's threat to seize six parks that could be closed to help reduce the state's ballooning budget deficit.

National Park Service Regional Director Jonathan Jarvis warned in a letter to Gov. Arnold Schwarzenegger that all six occupy former federal land that could revert to the U.S. government if the state fails to keep the parks open.

The sites are Angel Island, a former federal military and immigration facility in San Francisco Bay; the top of Mount Diablo east of San Francisco, where the Navy once operated a microwave relay station; Point Sur State Historic Park in coastal Big Sur; and three beaches -- Fort Ord Dunes near Monterey, Point Mugu State Park near Malibu, and Border Fields along the Mexican border.

The properties are among the 220 state parks Schwarzenegger has proposed closing to save $143 million. Legislators are considering the move as part of efforts to close a $26 billion budget deficit.

The Republican governor has rejected Democratic proposals to add a $15 fee to annual vehicle registrations to raise money to run the parks.

"Lands conveyed to the State under the Federal Lands to Parks Program must be open for public park and recreation use in perpetuity as a condition of the deed," Jarvis warned in a June 8 letter to Schwarzenegger made public Wednesday. "Any parkland thus conveyed, if it is found to be unavailable to the public for parks and recreation use, may revert to federal ownership for re-disposal."

The state could also lose future parks funding, Jarvis warned. California has received $286 million from the federal government since 1965 benefiting 67 parks on Schwarzenegger's closure list, Jarvis said.

"We're reviewing the letter and state parks director Ruth Coleman is in the process of talking with the National Park Service and Jon Jarvis about these very issues," said Schwarzenegger spokeswoman Lisa Page. "They are discussing a variety of outcomes and solutions depending on what final budget package is passed by the Legislature."

The National Park Service's California project manager, David Siegenthaler, but did not immediately return a telephone message Wednesday.

Jarvis said in his letter that California could consider options "short of park closures" that would keep the state in compliance with federal law. Neither Page nor California Department of Parks and Recreation spokesman Roy Stearns could immediately say what those options might be.

"Ruth has called him, talked to him, promised to find solutions and options that may keep the family intact, the park systems intact," Stearns said.

Stearns said park service officials are being cooperative, as Jarvis promised they would be in his letter.