At least four people were killed in clashes with Libyan security forces, opposition websites and NGOs said on Thursday, as the country faced a nationwide "Day of Anger" called by cyber-activists.
The websites and a Libyan rights group based in London said the clashes with demonstrators opposed to the regime of Libya's leader Moamer Kadhafi took place on Wednesday in the eastern town of Al-Baida.
"Internal security forces and militias of the Revolutionary Committees used live ammunition to disperse a peaceful demonstration by the youth of Al-Baida," leaving "at least four dead and several injured," according to Libya Watch.
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A Geneva-based rights group, Human Rights Solidarity, citing witnesses, said that snipers on rooftops had killed as many as 13 protesters and wounded dozens of others.
Videos circulating on the Internet showed dozens of young Libyans apparently gathered on Wednesday night in Al-Baida chanting, "The people want to bring down the regime," and a building which had been set on fire.
The scale of Thursday's protests will be a test for Kadhafi, 68, who has been in power since 1969, but whose counterparts in neighouring Egypt and Tunisia have been toppled in uprisings over the past month.
One Facebook group urging the Day of Anger, which had 4,400 members on Monday, had seen that number more than double to 9,600 by Wednesday following clashes in Benghazi, Libya's second largest city.
Quryna newspaper said security forces and demonstrators clashed late on Tuesday in Benghazi, also eastern Libya, in what it branded the work of "saboteurs" among a small group of protesters.
The director of the city's Al-Jala hospital, Abdelkarim Gubeaili, told AFP that 38 people were treated for light injuries.
Security forces intervened to halt a confrontation between Kadhafi supporters and the demonstrators, said the paper which is close to Colonel Kadhafi's son, Seif al-Islam.
Both Britain and the European Union called for restraint by the authorities in Libya, whose relations with the West have improved sharply over the past decade after years of virtual pariah status.
The European Union urged Libya to allow "free expression," while Britain underlined "the right of peaceful assembly."
The United States said it encouraged Libya, like countries throughout the Middle East and North Africa, to take steps to meet the hopes and needs of their people.
"Countries across the region have the same kind of challenge in terms of the demographics, the aspirations of their people, the need for reform," State Department Philip Crowley told reporters.
"And we encourage these countries to take specific actions that address the aspirations and the needs and hopes of their people," he added.
In the aftermath of the Benghazi protests, activists were rounded up in the opposition stronghold on Wednesday, according to an informed Libyan source, who declined to be named.
Amid the rivalry on the streets, pro-Kadhafi demonstrations were held in the capital late on Wednesday, on the eve of the Day of Anger called to mark the deaths of 14 protesters in an Islamist rally in Benghazi in 2006.
Also on the eve, text messages circulated across the Libyan mobile network from "the youth of Libya" warning against crossing "four red lines: Moamer Kadhafi, territorial integrity, Islam and internal security."
"We will confront anyone in any square or avenue of our beloved country," the message read.
The Revolutionary Committees, the backbone of Kadhafi's regime, have warned they would not allow anti-regime protesters to "plunder the achievements of the people and threaten the safety of citizens and the country's stability."
