Human Rights Watch said Sunday that the countrywide death toll in Libya had reached 173.

Local residents told Al Jazeera that 200 people had died in Benghazi alone.

Tripoli - The death toll has topped 100 from an iron-fisted crackdown on protests in east Libya, Human Rights Watch said, as demonstrators on Sunday again braved the streets of the restive city of Benghazi.

Speaking to Al-Jazeera television on a patchy telephone line, a Benghazi resident warned that the flashpoint city was turning into a scene of "out of sight massacres".

"It feels like an open warzone between protesters and security forces," said Fathi Terbeel, a protest organiser in Benghazi. "Our numbers show that more than 200 people have been killed ... God have mercy on them."

Another witness, identified only as Omar, told the Arab satellite that hundreds of angry protesters were gathered in front of Benghazi's court house after gunfire rang out downtown.

In what Britain has slammed as a "horrifying crackdown", the death toll from protests against Libyan leader Moamer Kadhafi's regime since Tuesday has risen to more than 100, according to Human Rights Watch (HRW).

"Our researcher in Libya has confirmed at least 104 deaths," HRW's Tom Porteous told AFP from London, with the overall toll based on reports from witnesses and medics.

"We are very concerned that under the communications blackout that has fallen on Libya since yesterday that a human rights catastrophe is unfolding," said Porteous, director of its London office.

The bloodshed peaked in Libya's second city of Benghazi on Saturday when mourners heading to the funerals of people killed by security forces targeted a military barracks on the route to the cemetery, witnesses said.

They threw firebombs at the barracks and troops responded with live rounds in which "at least 12 people were killed and many more injured," said Ramadan Briki, chief editor of the Libyan newspaper Quryna, citing security sources.

Before the latest round of bloodshed in Benghazi flared on Saturday, the New York-based HRW said security forces had already killed more than 80 anti-regime protesters in eastern Libya.

"Security forces are firing on Libyan citizens and killing scores simply because they're demanding change and accountability," it said.

After regime opponents used Facebook to mobilise the initial protests, the social networking website has since been blocked and Internet connections unreliable, according to Tripoli and Benghazi residents.

HRW said thousands poured into the streets of Benghazi and other eastern cities on Friday, a day after clashes in which 49 people were killed including in the city of Al-Baida where two policemen were reportedly lynched.

Libya's attorney general, Abdelrahman al-Abbar, ordered on Saturday an inquiry into the violence in the east, an official in Tripoli told AFP.

Kadhafi, 68, is the longest-serving leader in the Arab world. His oil-producing North African state was long a Western pariah, but relations had improved markedly in recent years.

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 have urged Libyan authorities to exercise restraint.

British Foreign Secretary William Hague urged Libyan authorities to rein in the security forces, and Washington had cautioned American citizens to steer clear of the restive east of Libya.

Meanwhile, Libyan authorities announced the arrest of dozens of non-Libyan Arabs across the country for allegedly stoking the protests.

Those detained were members of a "foreign network (and were) trained to damage Libya's stability, the safety of its citizens and national unit," the state news agency Jana said.

Kadhafi himself has made no public comment about the unprecedented challenge to his four-decade rule, part of a regional wave of popular uprisings that have already toppled the regimes of Libya's neighbours Tunisia and Egypt.

Source: Agence France-Presse