HAVANA (AP) — A Cuban punk rocker known for his raunchy lyrics criticising Fidel Castro was convicted of public disorder Friday, but freed after a court dismissed a more serious "social dangerousness" charge that could have sent him to prison for four years.

Following a two-hour trial, the court ordered Gorki Aguila to pay 600 pesos (US$28) and released the 39-year-old singer.

"I am very proud of all the people who have supported me, and I feel even more hate for this tyranny," Aguilar told reporters upon his release.

The fine is big money in a country where nearly everyone, Aguila included, works for the state and takes home an average of 408 pesos (US$19.50) per month.

But Aguila would have faced far more severe punishment had he been convicted of "social dangerousness," which the government defines as violating "communist morality." That charge is often used to detain would-be offenders before they have a chance to commit a crime.

Elizardo Sanchez, head of the independent Cuban Commission on Human Rights and National Reconciliation took the unusual step of attending the trial — which was open to Aguila's father and band mates as well as about 10 of his supporters, but closed to reporters.

"The prosecution asked for a fine," said Sanchez, whose group is not recognised but largely tolerated by Cuba's communist government. "Fortunately, there will be no more time in prison."

Aguila was arrested as his band, Porno para Ricardo, rehearsed at the modest Havana apartment he shares with his father. The case sparked international outcry but caused little stir on the island, where the band has only a small but devoted following.

Aguila was previously arrested in 2005 on drug charges that he says were fabricated because authorities objected to his music.

Founded 10 years ago, the band — whose name means "Porno for Ricardo" — is known for ridiculing the communist system, especially Castro, 82 and ailing, and his younger brother Raul, who became president in February. Its songs at one time were broadcast on state radio and TV, but the group was later banned and has resorted to small, occasional concerts in underground venues.

With long and wild curly black hair and healthy stubble, Aguila grinned and waved to supporters as officers loaded him in a police cruiser and drove him home. He will be allowed to pay his fine over time.

Aguila said Cuban authorities "want to teach me a lesson every chance they get," but were shocked by the international uproar. "There were a lot of repercussions, and they were very afraid."

Sanchez said on Friday before the trial that the "dangerousness" charge usually results in jail time for people who have not committed any crime.

"Because of 'social dangerousness,' thousands and thousands of Cubans are in prison," he said.

Band Guitarist Ciro Diaz said authorities told Aguila's state-assigned attorney he was arrested for being "an anti-social."

"His lawyer said he talked to the prosecutors, and that a judge told them this was a political trial," Diaz said outside the courthouse. "That this was about an undesirable in the neighbourhood who made songs with lyrics against the system, against Fidel and everything else."

Diaz said he and a friend were roughed up and arrested by state agents the previous night after they held up a handwritten sign reading "Gorki" at an open-air concert by legendary Cuban singer Pablo Milanes. He said they were treated for minor injuries and then interrogated for hours before being released without charge.