Manama: Embattled regimes across the Middle East cracked down on swelling anti-government protests on Friday, as the traditional Muslim day of prayer gave way to violence and bloodshed in Bahrain and Libya.

Bahraini police opened fire on protesters in the capital Manama, wounding dozens, as the army announced "strict measures" to restore security in the tiny but strategic Gulf monarchy shaken by unprecedented demonstrations.

In Libya, four days of unrest turned increasingly ugly, with 27 people reported to have been killed in protests in the east of the North African country ruled for more than four decades by Moamer Kadhafi.

A week after the overthrow of Egypt's president Hosni Mubarak, hundreds of thousands flooded Cairo's Tahrir Square to celebrate his departure.

But elsewhere, deadly violence flared as demonstrators inspired by the events in Egypt and Tunisia's ouster last month of its long-time ruler clashed with security forces.

Marchers in Manama had been trying to reach Pearl Square, the epicentre of pro-democracy protests that have shaken the Sunni-ruled Gulf island state, when security forces opened fire.

Witnesses said they were targeted by gunfire near Salmaniya hospital, about two kilometres (one mile) to the south.

"Twenty-six wounded people, including some with serious injuries, have been admitted to Salmaniya hospital," Shiite opposition MP Ali al-Aswad said. One of the wounded was "clinically dead", he said. It was the first demonstration since police stormed the square before dawn on Thursday, killing four people and wounding around 200 others.

Crown Prince Salman bin Hamad al-Khalifa promised to open a national dialogue once calm returns, a statement quickly backed by a royal announcement that he had been assigned to start such discussions. "What is happening today in Bahrain is not acceptable... We have reached a dangerous stage that necessitates that each of us acknowledges the responsibilities... Bahrain today is divided," Prince Salman said in an interview with state television.

US President Barack Obama spoke to King Hamad bin Issa al-Khalifa and condemned the violence in Bahrain, which is of vital strategic importance to Washington because the US Navy's Fifth Fleet is based there and some 40 percent of the world's oil passes through the Gulf.

Obama "strongly urged the government of Bahrain to show restraint, and to hold those responsible for the violence accountable," a White House statement said.

Kadhafi's regime also vowed on Friday to snuff out any challenge to the veteran Libyan leader, who has ruled his country with an iron fist since 1969.The Revolutionary Committees, which are the backbone of Kadhafi's regime, warned protesters in no uncertain terms."The response of the people and the Revolutionary Forces to any adventure by these small groups will be sharp and violent," the Revolutionary Committees said on the website of their newspaper, Azzahf Al-Akhdar (Green March).

According to a toll compiled, at least 41 people have lost their lives since demonstrations first erupted on Tuesday.The dead did not include two policemen reportedly hanged by protesters in the eastern city of Al-Baida, the Oea newspaper, which is close to Kadhafi's son Seif al-Islam, said.

Security forces were deployed around Al-Baida on Friday, a source close to the authorities revealed, following Internet reports that anti-regime protesters had seized control of the city. Protesters set fire to the headquarters of a local radio station in Benghazi after the building's guards withdrew, witnesses and a security source said.

Yemen, another ally of the United States in the battle against Al-Qaeda, also resorted to lethal force in the face of mounting protests, bringing the death toll since the unrest erupted on Sunday to 10. Anti-regime protesters in the volatile Yemen city of Taez were blasted in a hand grenade attack Friday leaving two dead, while fierce clashes in the southern city of Aden killed four, witnesses said.

Clashes also broke out in the capital Sanaa in which four anti-regime demonstrators were injured, according to witnesses and journalists, who were also beaten. The US embassy in Yemen slammed the attacks as "disturbing" and urged President Ali Abdullah Saleh to keep a pledge to uphold the right to peacefully demonstrate.

The Arab uprisings also inspired the opposition movement in Iran which staged an anti-government protest on Monday that ended in deadly clashes.Mir Hossein Mousavi and Mehdi Karroubi, former pillars of the Islamic regime who now are outspoken critics, have been placed under de facto house arrest and were the target on Friday of death threats at a pro-government rally.