TRIPOLI: Libyan authorities arrested dozens of foreign Arab nationals for allegedly stoking anti-regime protests amid reports that security forces had killed more than 80 people in a deadly crackdown.

Those detained in several Libyan cities were members of a “foreign network (and were) trained to damage Libya's stability, the safety of its citizens and national unity,” the official Jana news agency said, hinting that Israel was behind the alleged plot.

Sources close to the investigation, quoted by the agency late Saturday, said the group included Tunisian, Egyptian, Sudanese, Palestinian, Syrian and Turkish citizens.

The people arrested were “charged with inciting acts of looting and sabotage, such as burning hospitals, banks, courts, prisons, police stations and offices of the military police, as well as public buildings and private properties, according to plans drawn up earlier,” Jana said.

Noting that “certain Libyan cities have been the scene of acts of sabotage and destruction since Tuesday,” Jana said the suspects sought to “take arms from police stations and the military police and use them.”

“Sources close to the investigation have not ruled out Israel being behind the network,” the news agency added, without providing details.

Human Rights Watch meanwhile said security forces had killed more than 80 anti-regime protesters in eastern Libya in what Britain termed a “horrifying” crackdown.

On the fifth day of an unprecedented challenge to his four-decade regime, Libyan leader Moamer Kadhafi had still made no public comment.

After regime opponents used Facebook to mobilise protests, as in neighbouring Egypt, the social networking website was blocked and Internet connections were patchy, said Internet users in Tripoli and Benghazi.

Tripoli itself remained calm and state television and the official news agency restricted its coverage to reports of pro-regime rallies.

“Security forces are firing on Libyan citizens and killing scores simply because they're demanding change and accountability,” said New York-based Human Rights Watch (HRW), citing phone interviews with hospital staff and witnesses.

It said thousands of demonstrators had poured into the streets of Benghazi and other eastern cities on Friday, a day after clashes in which 49 people were killed.

“Hospital sources told Human Rights Watch that security forces killed 35 people in Benghazi on February 18, almost all with live ammunition,” raising the tally to more than 80.

At least 24 were gunned down in Benghazi, Libya’s second city and hotbed of anti-Kadhafi opposition, and on Al-Baida’s “day of anger” Thursday, according to HRW.

A medical source at Benghazi’s Al-Jalaa Hospital and the website of Quryna newspaper close to Kadhafi’s reputedly pro-reform son Seif al-Islam said Friday’s death toll in the city was 24.

Libya’s attorney general, Abdelrahman al-Abbar, has ordered an inquiry into the violence focused on the east of the country, an official in Tripoli told AFP, on condition of anonymity.

The prosecutor has called for “procedures to be expedited to judge all those who were guilty of death or looting,” the official said.

In Benghazi, demonstrators set fire to a local radio station Friday after the building’s guards withdrew, witnesses and a security source said.

And Quryna reported that some 1,000 inmates had escaped from a Benghazi prison, while a security source said four inmates were shot dead during a breakout bid in Tripoli.

According to a toll compiled by AFP from local sources, at least 65 people have been killed since demonstrations first erupted on Tuesday. That toll excludes two policemen that newspapers said were hanged in Al-Baida on Friday.

Oea, another newspaper close to Seif al-Islam, said the two policemen had been lynched by demonstrators.

Security forces circled Al-Baida on Friday, a source close to the authorities said, following Internet reports that protesters had seized control of the city.

Another well-informed local source said 14 civilians, including protesters and members of the Revolutionary Committees — the backbone of Kadhafi’s regime — had been killed in Al-Baida.

US President Barack Obama has condemned the use of violence against peaceful protesters in Libya, Bahrain and Yemen, while Britain, France and the European Union urged Libyan authorities to exercise restraint.

British Foreign Secretary William Hague denounced the crackdown, urging authorities to rein in the army.

Kadhafi, 68, is the longest-serving leader in the Arab world. His oil-producing North African state is sandwiched between Tunisia and Egypt, whose long-time leaders have been toppled by popular uprisings.