VIEQUES, Puerto Rico (CNN) -- Although protesters vow to return, the U.S. Navy has taken control of a bombing range on the Puerto Rican island of Vieques.

 Military planners said they needed to use the weapons range very soon for training exercises involving the dropping of non-explosive ordinance.

 "We are hopeful that it will be within weeks," Rear Adm. Robert Natter said during a Pentagon briefing hours after FBI agents, federal marshals and local police cleared nearly 213 protesters from the restricted area on the island.

 The year-long standoff between the U.S. Navy and non-violent protesters ended with a raid early Thursday. When protesters ignored a final warning to disperse, FBI agents in riot gear began pouring out of vehicles.

 "So far the operation has gone very smoothly," U.S. Attorney General Janet Reno said, just hours after the evictions. Reno spoke to reporters at her weekly news conference in Washington.

 White House Spokesman Joe Lockhart said President Clinton was "pleased the operation moved forward in a peaceful fashion."

 Coast Guard patrolling waters off Vieques

 Among those protesters evicted from the area was U.S. Rep. Luis Gutierrez, D-Illinois.

 "They may remove us, but there will be many others to follow," Gutierrez told reporters as he was led away.

 To head that off, Navy officials said some 200 Marines had gone ashore on an amphibious landing craft to set up a security perimeter around the U.S. Navy base on the eastern end of the 54-square-mile island.

 Reno said the U.S. Coast Guard has established a security zone in the waters around the base to prevent additional protesters from arriving by boat.

 The Coast Guard said it stopped 21 vessels on Thursday and would continue patrolling the three-mile zone through May 13.

 Also among the U.S. politicians on the island, according to two White House officials, were Rep. Nydia Valazquez, D-New York, New York City Councilman Jose Rivera and New York state assemblyman Roberto Ramirez.

 One of the White House officials said the four had informed federal officials they were there to encourage the protesters to remain peaceful, and had said they intended to be arrested with those at the scene.

 'Vieques has been abused, has been misused'

 Although many of the protesters asked to be handcuffed before being led away to transport trucks, the FBI said no one was being arrested, only held in custody.

 But authorities warned the demonstrators that if they returned to the bombing range, they would face arrest. A trespassing conviction could mean fines and sentences of up to six months in prison.

 Hours after his fellow Puerto Rican lawmakers were evicted from the base on Vieques, Rep. Jose Serrano staged a lonely protest outside the White House where he was handcuffed and led away by park police.

 Before his arrest, Serrano told reporters he and other lawmakers had written to President Clinton asking him not to go trough with the arrests on Vieques and to call an immediate referendum in Puerto Rico on the issue.

 "For over 60 years, Vieques has been abused, has been misused," Serrano said. "For me, it is very painful. I was born in the colony and now I'm a member of a Congress of a colonial power that holds the colony."

 About 12 hours after the FBI moved in, the responsibility for security at the Vieques military firing range officially shifted from the Justice to Defense Department. Rear Adm. David Ellison of the U.S. Navy is now the on-scene commander.

 Wayward bombs started dispute

 Protesters invaded the range last year after two 500-pound bombs landed off-target, killing civilian security guard David Sanes Rodriguez, 35, on April 19, 1999.

 The Navy says the range is vital to U.S. national security as the only place its Atlantic fleet can conduct simultaneous air, sea and amphibious training using live munitions.

 The range has been used to prepare for conflicts involving the U.S. military since World War II, when the United States began its purchase of up two-thirds of the 52-square-mile

 Protesters have demanded the U.S. Navy stop bombing, clean up toxic chemicals and unexploded ordnance at the base and return the land to residents.

 Even Latin pop superstar Ricky Martin, arguably the most famous Puerto Rican, weighed in with a personal appeal to President Clinton to close the range.

 Natter said the range on the eastern tip of Vieques will be thoroughly searched for straggling protesters before training will resume.

 "We're going to search the area as best we can. We think it's going to be very thorough. Some of it will be done on ground, a lot of it will be done from the air," the U.S. Navy admiral told reporters.

 The Clinton Administration negotiated a deal in January with the Puerto Rican government to limit military training to the use of non-explosive "inert" bombs until the island's 9,300 residents vote in an as-yet unscheduled referendum.

 They will decide whether to accept up to $90 million in economic aid in return for allowing the Navy to resume exercises with live ammunition.

 National Correspondent Mike Boettcher, The Associated Press and Reuters contributed to this report.