Illegal immigrants who hike through the rugged forested mountains of eastern San Diego County after making it across the border are causing a dramatic surge in wildfires because of fires they light when camping out in the area, state and county officials said today.

The number of wildfires in the region since January is already four times last year's total, a frightening jump that has prompted the San Diego County Board of Supervisors to declare a state of emergency and ask President Clinton to deploy U.S. troops near the border to prevent the immigrants from entering the forests.

Miller said that up to 2,600 illegal immigrants cross the California border each day, and that increasing numbers of them are heading to the rugged mountains to avoid Border Patrol checkpoints on northbound highways along the Pacific coast.

The immigrants normally live in the wilderness one to four days, usually sleeping during the day and hiking at night. They often build their campfires amid vegetation that grows to 12 feet high and then leave them unattended when they move on.

The fire chief said he had been told by Border Patrol agents that sometimes the immigrants intentionally start wildfires to create a diversion when they think they have been detected.