SAN JUAN, Puerto Rico (AP) _ A federal judge in Puerto Rico sentenced a U.S. congressman to a three-hour prison term and probation on Wednesday for trespassing during protests against Navy bombing on Vieques Island.

Rep. Luis Gutierrez, a five-term Democrat from Illinois, was allowed to serve his three hours at the U.S. Marshals office within the U.S. District Court building in San Juan, the capital.

``I don't like breaking the law, but there is no alternative left to us besides peaceful civil disobedience,'' said Gutierrez in court before sentencing. He was to be released Wednesday afternoon.

Anti-Navy sentiment on Vieques swelled after a civilian guard was killed by off-target bombs in 1999, prompting the Navy to switch to inert ammunition. President Bush has promised to end the maneuvers by 2003, but anti-Navy activists want the bombing halted immediately.

Judge Salvador Casellas also sentenced Gutierrez to six months probation.

The sentence was among the most lenient handed down by the federal courts in Puerto Rico against Vieques protesters.

Navy sailor Paulo Fleurant testified that Gutierrez resisted arrest after breaking through a fence into Navy lands on April 28. But under cross-examination, Fleurant said that he never registered a complaint on the alleged incident.

Judge Casellas said there was no hard proof that Gutierrez was uncooperative with Navy security.

Gutierrez was one of some 180 people _ including politicians and several celebrities _ arrested during Navy exercises in April and May.

Gutierrez had claimed he was mistreated after his arrest, saying he had his feet kicked out from under him by Navy security on Vieques. He said he was held overnight on Vieques before being processed by U.S. authorities in Puerto Rico.

The Navy said security acted with restraint in all cases and said any delay in processing was due to the large amount of detainees.

Civil rights leader the Rev. Al Sharpton, environmental lawyer Robert F. Kennedy and actor Edward James Olmos were sentenced to 20- to 90-day prison terms for trespassing in protests during the April and May exercises. All have been released.