Sun Feb 17, 2008 1:29pm EST MANAMA (Reuters) - Bahrain should investigate complaints that detained opposition activists have been repeatedly abused in jail, Western human rights groups said.

U.S.-based Human Rights Watch called on the Gulf Arab state's government to allow independent doctors to examine detainees who say they have faced torture and sexual assault.

"The silence of Bahraini authorities in the face of multiple complaints of detainee abuse casts doubt on their commitment to the rule of law," said Joe Stork, Middle East and North Africa director at Human Rights Watch, in a weekend statement.

"Bahrain should immediately allow independent physicians to examine detainees who are alleging abuse."

The detainees were among those arrested after protests by majority Shi'ites in the U.S.-allied island state in December.

The Observatory for the Protection of Human Rights Defenders said in a statement on Sunday it had received reports that prisoners were subjected to beatings, verbal abuse and threats, and deprived of sleep and food. Some were kept in solitary confinement or handcuffed or blindfolded for long periods.

Officials have said some of the detainees are suspected of setting ablaze a police vehicle after taking weapons from it.

Shi'ites complain of discrimination, but the authorities say there is none and cite limited resources in the Gulf Arab region's least wealthy country.

Violent protests gripped Bahrain during the 1980s and 1990s when Shi'ite demands were met with arrests and expulsions.

Since coming to power in 1999, King Hamad bin Isa al-Khalifa has introduced some reforms, including pardoning political prisoners and exiles.

(Writing by Firouz Sedarat; Editing by Catherine Evans)

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