Gulf Arab states on Saturday turned up the heat on Damascus, joining a growing chorus of pressure after Syrian security forces shot dead at least 22 people as tens of thousands staged anti-regime protests.

The six-member Gulf Cooperation Council called for an "immediate end to violence... and bloodshed."

The State Department on Friday urged Americans in Syria to leave the country immediately and advised those who remain in the country to restrict their movements, as the Syrian government intensified a violent crackdown on opposition protesters.

The warning came as congressional calls grew for the Obama administration to impose severe new sanctions on President Bashar Assad's regime.

Iran's Foreign Minister Ali Akbar Salehi hopes that the trial of two U.S. citizens detained in the Islamic republic on espionage charges will lead to their freedom, local media reported Saturday.

"We hope that the trial of these two (U.S.) nationals will proceed in a manner that will result in their freedom," Salehi was quoted as saying by Fars news agency.

Four prisoners and a guard were killed in clashes at a prison in the central Iraqi city of Hilla, during which eight inmates escaped, officials said on Saturday.

The clashes, in which nine people were also wounded, broke out after a prisoner seized a rifle from a guard and killed him, said Mohammed Ali al-Massudi, the governor of Babil province, of which Hilla is the capital.

Activists said Saturday that at least 24 Syrian civilians have been killed as security forces fired on anti-government protesters as part of a nationwide crackdown.

Syria-based rights activist Mustafa Osso said most of the deaths occurred in Damascus suburbs during daytime Friday protests and late night demonstrations following evening Ramadan prayers.

U.S. officials and their counterparts in Bahrain, which crushed month-long protests in mid-March, have renewed a defense pact, officials said Friday.

The two countries inked a 10-year defense agreement on October 28, 1991, seven months after the Gulf War, that was renewed in October 2001 for the same duration.

Security forces shot dead a gunman as he opened fire on the Jeddah palace of Saudi Interior Minister Prince Nayef bin Abdul Aziz early on Saturday, said a source close to the government.

Another man was arrested during the attack in which "two men opened fire after midnight on the Qasr Shateh residence of Prince Nayef (and) the security forces retaliated, killing one of them," the source told Agence France Presse.

The U.S., French and German leaders pledged to consider new steps to punish Syria after security forces shot dead at least 24 people as tens of thousands staged anti-regime protests on the first Friday of Ramadan.

President Barack Obama spoke separately to France's Nicolas Sarkozy and German Chancellor Angela Merkel as Western nations cranked up pressure on Syrian leader Bashar al-Assad.

Ousted president Hosni Mubarak, convicted for having cut Internet services during the revolt which toppled him, has pinned part of the blame on his successor as Egypt's ruler, a defense lawyer said on Friday.

A Cairo court on May 28 fined Mubarak and two former ministers a total of $90 million dollars for "damaging the economy" with a telephone and Internet shutdown during Egypt's uprising.

An explosion struck an oil pipeline in Iran's oil-rich southwestern province of Khuzestan early Friday, triggering a blaze that took firefighters hours to put out, news agencies reported.

Abdohossein Rezaeizadeh, spokesman for the provinces' branch of the Iranian national oil company, told the official IRNA news agency that the causes of the blast and the subsequent fire were under investigation.