Angel Morey, Puerto Rico's secretary of state, said he had voiced concerns to the Navy on Sunday over the possibility of stray protesters being hit by inert ordnance.

"Today's exercises occurred in open terrain and in a smaller area (than usual) to minimise" that threat, Mr Morey said.

Six demonstrators were detained over the weekend and two others on Monday in the range.

But the US Navy said there was no more protesters on the islands.

"In addition to the two individuals detained today, we have not identified any additional personnel on the range," Robert Nelson, a Navy spokesman, said.

Trespass

The leader of the Puerto Rican Independence Party, Ruben Berios, has announced plans to trespass on the training base on Tuesday.

Several other church leaders from Puerto Rico say they will also try to reoccupy the Vieques training facility.

The demonstrators say the bombing has damaged the environment, destroyed the economy and caused health problems among residents.

The Navy says the island provides vital training for US forces.

The arrests sparked demonstrations

Mr Nelson said the training "consisted of several Roosevelt Roads-based aircraft using air-to-ground inert ordnance."

He added that the exercise took place with the knowledge of the government of Puerto Rico.

A 1983 Memorandum of Understanding calls for the Puerto Rican government to be notified of any training at the range.

Agreement

The protesters stood in the way of implementing an agreement reached by US President Bill Clinton and Puerto Rican Governor Pedro Rossello to permit the American Navy to resume limited training with "dummy" bombs.

In exchange, residents of Vieques would have an opportunity to vote on whether the American military should leave Vieques by 2003.

Most analysts say islanders would say "No" to the navy, which has acknowledged it failed to implement a 1983 accord to promote Vieques' economic development.