MANAMA: A Bahraini woman, who rights group Amnesty International said was jailed for listening to a revolutionary song in her car, has been released and given a hero's welcome by a 10,000-strong opposition rally, a rights activist said on Tuesday.

Fadhila al-Mubarak was detained during martial law last year at a checkpoint for listening to a tape praising a pro-democracy protest movement that erupted in February after uprisings in Egypt and Tunisia, Said Yousef al-Muhafda said.

Mubarak was sentenced to four years in jail for taking part in the Pearl Roundabout protests, inciting hatred of the government and insulting a public official, Muhafda said. The sentence was later reduced to 18 months and must still be appealed.

“She didn't stop playing the song and that's why they got angry. It was a personal thing,” he said, referring to the officers who arrested Mubarak. She was freed on Monday.

Demonstrations and clashes with police have escalated in recent weeks in the run-up to the February 14 anniversary of the start of the protests. The opposition want to reduce the ruling Al Khalifa family's domination of power through allowing the elected parliament to form governments.

The Gulf Arab state's Shi'ite majority also complain of economic marginalisation and attempts by the Sunni rulers to give Sunni foreigners nationality to offset Shi'ite demographic strength, claims the government denies.

Bahrain is host to the US Fifth Fleet and is seen by Washington and Riyadh, which sent troops to help crush the protest movement in March, as a key ally in their conflicts with Iran over its nuclear energy programme and regional influence.

Amnesty International last month called for Mubarak's release and called for an investigation into allegations of mistreatment she suffered while in detention and during her arrest.

Muhafda said Bahraini authorities also released a Canadian national of Kuwaiti origin called Nasser al-Rass who was sentenced to five years in jail for taking part in protests.