VIEQUES, Puerto Rico (AP) _ With U.S. warships looming offshore, protesters held an all-night vigil today blocking a contested Navy bombing range on Vieques Island, amid reports that federal agents were planning to evict them.

At sunrise, the activists broke into applause to celebrate their continued stand outside the gates of the base, after a night spent playing dominos, reading, praying and preparing for a raid they believe is imminent.

``The people have been here 379 days _ and we can stay here 379 months if necessary,'' declared a jubilant Robert Rabin, one of the protest organizers. As some 50 protesters ate breakfast and sipped coffee, a Humvee carrying eight soldiers drove slowly past.

Tensions increased Monday with reports that the USS Nashville and USS Bataan picked up 1,000 Marines in North Carolina en route to Vieques. The Marines reportedly would secure the range's perimeter once protesters are removed. Arrests would be carried out by federal agents in an FBI-led operation, according to Pentagon officials.

``I'm not going to fight with them,'' said Luisa Guadalupe, 82, one of the protesters. ``But to get me out of here they're going to have to arrest me.''

Puerto Rico Gov. Pedro Rossello _ who supports both the removal of the protesters and the eventual closure of the Navy base _ said local authorities were ready to deal with any unrest, though he predicted that wouldn't be necessary.

``I believe the Puerto Rican people won't participate in illegal acts,'' he said Monday. ``However, we are prepared at any time ... to establish law and order.''

Navy exercises that had been held for 60 years on the island, just east of Puerto Rico, were suspended a year ago after stray bombs killed a civilian security guard, releasing pent-up resentment in the U.S. territory.

Protesters at several camps inside the range stand in the way of an agreement between President Clinton and Rossello to allow limited training exercises at the base until Vieques' 9,300 residents decide in a referendum whether the Navy should leave.

On Monday, three U.S. warships appeared off Vieques' north coast, accompanied by two Coast Guard vessels. The hull number on one of them was 13, corresponding to that of the USS Nashville, an amphibious transport. The Bataan is an amphibious assault ship.

The warships later steamed off to nearby Roosevelt Roads Naval Station on the main island of Puerto Rico. An Army barge, meanwhile, delivered Puerto Rican riot police vans to Vieques.

Several Navy helicopters flew over the range.

Most protesters planned to surrender peacefully. But a few threatened to scatter into the bomb-littered bush, raising the specter of a dangerous hunt.

Protesters also say they will cut through fences and ride in by horseback to replace any demonstrators who are arrested.

Up to 150 people gathered outside the range's main gate late Monday for the vigil. In the early hours this morning, organizers showed protesters where to find jars of petroleum jelly and goggles to use as protection against pepper spray. They also handed out small plastic bags, each with a rag soaked in a vinegar-water mixture to minimize the effects of any spray or tear gas.

``We want to provoke arrests. We want to obligate them to arrest us,'' Rabin told the protesters. ``But we are not going to be fighting with the police.'' He told them to get rid of anything resembling a weapon _ even a pocketknife.

Four observers from the government Civil Rights Commission arrived with fliers explaining protesters' rights if arrested.

At a Roman Catholic Mass, the Rev. Pedro Rafael Ortiz said the bombing has caused ecological damage and ``slow deaths,'' alluding to high cancer rates. ``God wants us to be in this struggle,'' he said. ``The Navy needs to repent for the evil it has done and not sin again.''

Local politicians arrived Monday to reinforce the gate camp and said arrests would anger Puerto Ricans in New York, Florida and Chicago _ much as the Justice Department raid to seize Elian Gonzalez from his relatives' home in Miami enraged the Cuban-American community there.