Human Rights Watch said on Wednesday that Bahrain authorities were harassing and isolating hospital patients wounded in anti-government protests when security forces began a crackdown in the kingdom two weeks ago.
Bahrain's Sunni rulers this month imposed martial law and brought in troops from Sunni-led Gulf neighbours, including Saudi Arabia, to quell weeks of unrest during pro-democracy demonstrations led mostly by the state's Shi'ite majority.
Twenty-four people were killed in the ensuing clashes, the government said on Tuesday. The opposition Wefaq party says 250 people have been detained and another 44 have gone missing since the crackdown.
The security measures were condemned by Iran, the main Shi'ite power in a region dominated by Sunni Muslim rulers, which said they could lead to a wider conflict.
Foreign Minister Sheikh Khaled al-Khalifa said Iran should stop its "offensive" against Bahrain, telling pan-Arab daily al-Hayat that political dialogue could only start once security had been restored in the island kingdom. Opposition parties reiterated denials of any foreign backing on Wednesday.
US-based Human Rights Watch said it was concerned Bahrain forces were targeting hospital patients who were protesters or bystanders in scattered demonstrations that broke out last Friday in a planned "Day of Rage" that police quickly quashed.
"Human Rights Watch (HRW) has documented several cases in which patients with protest-related injuries were transferred to or sought treatment at Salmaniya and were then severely harassed or beaten," it said in a statement.
In the March 16 crackdown, Bahraini forces took over Salmaniya medical centre, the country's largest public hospital.
Bahrain's government has said it raided the hospital because it had been "overrun by political and sectarian activity".
HRW's report comes a day after the Interior Ministry released a statement calling on Bahrainis not to avoid hospital care, as it could cause their condition to deteriorate.
The rights group said the ministry had not dealt with patients' fears about harassment.
"These people who need treatment are facing this difficult choice, and many choose not to go to the hospital," HRW's Bahrain researcher Faraz Saneif told Reuters.
"It will be an ongoing problem as disturbances continue in villages surrounding Manama."
HRW cited several cases where patients were quickly picked up by police after they gave hospitals their identification and cited the cause of their injuries as tear gas, rubber bullets and birdshot, which were all used to disperse protesters.
Security forces told HRW the patients were transferred to Salmaniya hospital or the Bahrain Defence Force hospital for surgery. HRW said the patients' families were given no information on the whereabouts or condition of their relatives.
More than 60 percent of Bahrainis are Shi'ites and most are calling for a constitutional monarchy. But demands by hardliners for the overthrow of the monarchy have alarmed minority Sunnis, who fear unrest serves Iran.
Sheikh Khaled told al-Hayat that Bahrain did not want Iranian mediation and called on "Iranians to stop this offensive that we have been exposed to."
Bahrain's main Shi'ite opposition group Wefaq and six smaller opposition groups rejected claims by the government that protests were organised by outside forces and said Bahrainis were striving for democracy and freedoms.
"We don't want Bahrain to be a place for other countries to settle their accounts," Wefaq leader Sheikh Ali Salman told a news conference in Manama.
Talks offered by the crown prince in early March, initially bogged down by debates on conditions, were dropped after the crackdown.
"The priority now is to return to security and order. There's no doubt that a political process will start and develop, but only after we've restored stability," Sheikh Khaled said.