Manama, Bahrain (CNN) -- U.S. Secretary of State Hillary Clinton called on Bahrain on Saturday to allow its people to demonstrate peacefully as opposition members reported the death of a fifth protester this week.

Essa Radhi Al Radi was killed Tuesday when Bahraini security forces cleared protesters from the Pearl Roundabout in the capital, Manama, said Khalil Al Marzook, a leading member of the opposition Wefaq party.

Al Radi's family received a phone call Saturday from a hospital telling them he had died but giving few other details, Al Marzook said.

Al Radi was the fifth protester who died this week after a crackdown by security forces, Al Marzook said. One was killed Tuesday and the other three were killed Wednesday, he said.

Human rights group Amnesty International reported eight people were killed Wednesday when security forces forcibly removed demonstrators at the roundabout. It said at least one of the dead was a member of the security forces, but that the majority of the dead were protesters.

The discrepancy in death tolls could not immediately be explained.

Thousands of people have been demonstrating in Bahrain since last month, part of a wave of unrest that has spread through North Africa and the Middle East. Many of them congregated at the roundabout and were there until as recently as this week, when security forces cleared the area and the government demolished the landmark monument at the center of the traffic circle.

Clinton said she had spoken about Bahrain on Saturday with the foreign minister of the United Arab Emirates and prime minister of Qatar, on the sidelines of a meeting in Paris about Libya.

"Our goal is a credible political process that can address the legitimate aspirations of all the people of Bahrain, starting with the crown prince's dialogue, which all parties should join," Clinton said. "That process should unfold in a peaceful, positive atmosphere that protects the freedom of peaceful assembly while ensuring that students can go to school, businesses can operate, and people can undertake their normal daily activities."

The United Arab Emirates and Qatar, like Bahrain, are members of the six-nation Gulf Cooperation Council. At Bahrain's request, military forces from the council are in Bahrain to help control the anti-government demonstrations.

Clinton said Bahrain has a right to invite those forces into its country, but she urged caution.

"We have made clear that security alone cannot resolve the challenges facing Bahrain," Clinton said. "Violence is not and cannot be the answer. A political process is. We have raised our concerns about the current measures directly with Bahraini officials and will continue to do so."

The U.S. State Department and Amnesty International expressed concern Friday about the arrest in Bahrain of several prominent opposition figures. Amnesty said they were arrested in armed raids and that authorities produced no arrest warrants.

Also Friday, two doctors from Salmaniya Hospital said security forces were beating patients and had removed "six to 10 patients," and some medical records, from the facility.

U.N. High Commissioner for Human Rights Navi Pillay expressed concern at reports that security forces were targeting hospitals. She said her office had been receiving "desperate calls" regarding, among other things, security forces taking over hospitals and medical centers.

Bahrain's government Friday announced it was shortening a nightly curfew that had been declared for a central part of Manama in order to ease the movement of citizens there.

The curfew, which had been from 4 p.m. to 4 a.m. each night, will now stretch from 8 p.m. to 4 a.m., the state-run Bahrain News Agency reported.

At the same time, the country's defense force imposed a marine curfew, which bans any sea activity, between 5 p.m. and 6 a.m. each night until further notice, the news agency reported.

CNN's Leone Lakhani contributed to this report