Bahrain has arrested at least 60 Shi'ite protest leaders in recent days to try to prevent widescale unrest ahead of a controversial Formula One Grand Prix this week, activists said on Tuesday.
News of the crackdown coincided with a statement from Amnesty International which said it was getting credible reports of the use of torture in the Gulf Arab state despite promises of reform.
The authorities are trying to portray the country as being on the road to reform, but we continue to receive reports of torture and use of unnecessary and excessive force against protests, Hassiba Hadj Sahraoui, Amnesty International's Middle East and North Africa deputy director, said in a statement.
Their reforms have only scratched the surface.
Bahrain is gearing up to host a prestigious Grand Prix on April 20-22, an event that was cancelled last year because of unrest and one it hopes will improve its international image and show it is serious about reform.
In particular, it is eager to show that the country's Sunni Muslim rulers have repaired relations with the majority Muslim Shi'ite community after last year's protests, which were put down with the help of troops from neighbouring Saudi Arabia.
Bahrain's Shi'ites complain they are given fewer opportunities and access to jobs and housing than the Sunni elite.
But activists said on Tuesday that relations between the two communities were still badly strained by routine violence.
They said riot police had used live ammunition for the first time since last year's pro-democracy protest movement was crushed, firing bullets into the air.
We have evidence in photographs and video from April 13 in Diraz and Sitra, said Mohammed al-Maskati, head of the Bahrain Youth Society for Human Rights.
The Shi'ite-led opposition holds weekly large-scale rallies calling for democratic reform, while Shi'ite youths clash nightly with riot police.
It started in Bani Jamra last Thursday, then Sitra, Ghuraifa, Diraz, Ma'amir and Sehla, said Maskati.
Those arrested are activists in the villages. The authorities are afraid that some people will go to protest in Manama or close to the area of the race.
Sixty people remained in custody, he said.
Interior ministry spokesmen and foreign advisers were not available to confirm the arrests or the use of live fire.
Violence has escalated in Bahrain, a key U.S. ally that hosts its Fifth Fleet, ahead of the Grand Prix.
Sayed Yousif al-Muhafda of the Bahrain Centre for Human Rights, a separate group, also said police had seized dozens seen as protest organisers in late-night raids in the past week.
Separately, Amnesty said Bahrain's government has failed to adopt key reforms recommended by an international panel of human rights experts. Bahrain government officials were not immediately available to comment.
The government brought in a commission of human rights experts last year to propose reforms. The government later said the kingdom had agreed to a new police code of conduct and had set up a body to investigate accusations that government employees killed or mistreated citizens.
Amnesty said some of the commission's proposals had been adopted, but said a lot more needed to be done.
In particular, holding to account senior members of the security forces accused of violations, releasing prisoners of conscience and addressing the underlying discrimination against the Shi'ite majority population, it said.
Thirty-five people died during the unrest last year, but since martial law ended in June the total has risen to around 70, activists say. They cite heavy use of tear gas, but the government questions whether the gas killed anyone.
(Additional reporting by Reed Stevenson; Editing by Andrew Osborn)