(CNN) -- A prominent Bahraini activist was severely beaten by security forces at a protest Friday, according to the human rights group that he leads.
Nabeel Rajab was hospitalized and later released, with injuries to his head, back and chest, according to the website of his group, the Bahrain Center for Human Rights.
A protester, who spoke on the condition of anonymity, said Rajab has trouble standing now.
"He is able to talk and walk, with some difficulty because he has some pain in his back," the protester said. "After the police realized he was Nabeel Rajab it was completely different treatment afterward. They took him to hospital. He heard that the leader of the group asked them to stop beating him when they realized he was Nabeel Rajab."
The activist's supporters had gathered to wait for his return at his home in the town of Bani Jamra. They were attacked by security forces, firing tear gas, Maryam Khawaja, head of foreign relations for the center, told CNN, citing witnesses.
Some protesters ran away; others ran into the house. No one was injured, according to the protester who spoke on the condition of anonymity.
"Rajab is being treated for injuries at Salmaniya hospital, along with activist Said Yousif of the Bahrain Center for Human Rights, who was hit in the leg with a stun grenade," activist Zainab Alkhawaja said before Rajab's release from the hospital.
CNN was not immediately able to reach Bahraini officials at the president's office for comment.
In May, Rajab's house was tear-gassed as he and his family slept, the Bahrain Center for Human Rights said. That followed a similar attack in April.
Human Rights Watch said then that it knew of no entity other than Bahrain's security forces that would have access to the kind of grenades used in the April attack.
"This has been a fear for some time. Many were fearing (for) the safety of Nabeel," said Jasim Husain, an Al Wefaq party member and a former member of Bahrain's lower house.
"At least we know he is safe and recovering," Husain said before word of Rajab's release from the hospital. "The authorities need to explain."
The outspoken activist has often appeared on CNN, complaining about the use of violence and torture against pro-democracy protesters at the hands of Bahraini security forces.
Rajab was presented with the Ion Ratiu Democracy Award by the Woodrow Wilson Center in Washington in November.
Husain described Rajab as one of the most famous figures in the country, who pushes for change through peaceful means.
Another activist, 18, remained in detention Friday after being arrested this week, marking the fifth time he has been arrested for political reasons in the last 18 months, the Bahrain Center for Human Rights said. During previous detentions, he was allegedly raped, repeatedly, the center said. His lawyer, who saw the teenager a day after his latest arrest, told CNN he was limping and showed signs of having been struck in his face and leg.
"They arrested him because he and my brothers are well-known activists in our village and he participated in many protests," the detainee's sister told CNN. She said her brother had contacted the Bahrain Center for Human Rights and told officials there about the torture he allegedly suffered during his previous detention.
Amnesty International released a statement in which it said it feared the 18-year-old may have been targeted again because he reported the abuse.
CNN does not identify rape victims.
On Monday, Bahrain's top court announced that it is creating a judicial panel to review some military court verdicts related to protests last year, the state news agency said.
"A new judicial body comprising a number of judges from the civil courts shall be created in order to review nonappealable verdicts issued in favor of conviction by national safety courts according to international principles of the right to undergo a fair court trial and to access a lawyer for assistance in order to achieve the principles of fair justice," said Sheikh bin Rashid Al Khalifa, the Supreme Judicial Council's deputy chairman and president of the Court of Cassation.
He was quoted by the state-run Bahrain News Agency.
The new judicial body will review nonappealable convictions pertaining to freedom of expression, but not those related to incitement of violence, it said. The judicial body will then submit the cases to the Supreme Judicial Council "in order to take appropriate actions," it said.
The announcement came a day after witnesses said hundreds of mourners walked the streets of Sitra, south of the capital, behind the coffin carrying the body of a 16-year-old boy who was killed during protests Saturday.
Clashes also occurred Sunday in Sitra between protesters and security forces that fired tear gas at them, injuring several people, witnesses said.
In a New Year's message, Chief of Public Security Tariq Al Hassan announced that 500 officers will be recruited from all sections of Bahrain society in an effort to improve community relations. The officers will wear distinctive uniforms and police only the areas from where they have been recruited, he said.
Noting the highly critical report issued in November by Bahrain's Independent Commission of Inquiry, which looked into the violence, Al Hassan said the task now "is to look at where we've gone wrong, to face our mistakes and learn lessons."
"I am determined to make people understand that we have a responsibility to ensure that whoever breaks the law will be held accountable, whether it is a private citizen or a policeman," said Al Hassan, who has 30 years of experience in Bahrain's police force and studied public security in the United States and Britain.
The commission, set up by the king, concluded that police had used excessive force and torture during last year's crackdown on protests. Abuse of detainees included beatings with metal pipes and batons, and threats of rape and electrocution, commission Chairman Mahmoud Cherif Bassiouni said in November.
The mistreatment included physical and psychological torture, intended to extract information or to punish those held by security forces, he said.
The report recommended reforms to the country's law and better training of its security forces.
Protests demanding political reform and greater freedoms in Sunni-ruled, Shiite-majority Bahrain began February 14 before authorities -- backed by troops from Saudi Arabia and the United Arab Emirates -- cracked down on the demonstrations, first in February and later in mid-March.
CNN's Amber Lyon and Samira Said contributed to this report.