SANAA/CAIRO Protests erupted across much of the Arab world on Friday, the Muslim day of prayer, with demonstrators killed in Syria and Yemen while Egyptians staged one of the biggest rallies since President Hosni Mubarak's fall.
Syrian security forces killed 17 pro-democracy demonstrators and two were shot dead in Yemen. In Saudi Arabia local Shi'ites protested in the oil-producing east to call for the withdrawal of Saudi troops from neighboring Bahrain.
In Cairo's Tahrir Square, perhaps the spiritual home of the Arab protest movement, crowds demanded Mubarak's prosecution as discontent with military rule grows; but in Oman heavy security prevented a planned demonstration after Friday prayers.
Friday has become a peak day of protest for many Arabs since popular demands for freedom, democracy and an end to corruption began in Tunisia late last year and spread across the region.
In Syria, security forces opened fire on thousands of demonstrators in the southern city of Deraa as protests against President Bashar al-Assad flared in several towns.
A hospital source and an activist reported 17 dead in Deraa, where protests began last month before spreading across the country.
"There were snipers on roofs. Gunfire was heavy. The injured are being taken to homes. No one trusts putting his relative in a hospital in these circumstances," said a witness, who spoke to Reuters by telephone.
Authorities have blamed armed groups for the violence, and state television broadcast footage of masked gunmen in plain clothes it said fired at security forces and civilians alike. It said a policeman and an ambulance driver were killed.
Syria has prevented other media reporting from Deraa.
In eastern Syria, ethnic Kurds demonstrated for reform despite Assad's offer this week to ease rules which bar many of them from obtaining citizenship, activists said.
NO ORDERS OR INTERVENTION
Violence also broke out in Yemen as crowds demanded the overthrow of President Ali Abdullah Saleh. Two people were shot dead and 25 wounded by gunfire in the southern city of Taiz, hospital sources said.
But Saleh rejected any aspect of a Gulf Arab mediation plan for talks with the opposition that would aim to end his 32-year rule. "The Yemeni people are free to accept mediation from their brothers and friends, but they reject taking orders or intervention," Saleh said in a statement.
Elsewhere, the day of protest was more peaceful.
Tens of thousands of Egyptians in Tahrir Square demanded Mubarak's prosecution and accused the military of being too slow to root out corruption from his era.
"Oh, Field Marshal, we've been very patient!" chanted some of the demonstrators in the square, hub of the movement that toppled Mubarak on February 11 and left the army in charge, led by Field Marshal Mohamed Hussein Tantawi.
Friday's protest had swollen by early afternoon to at least 100,000, indicating growing frustration with the army which has enjoyed broad support since it took control of the country.
"It's a strong message that the revolution is not over yet and is still going on and will not quieten down before its goals are realized," said Hassan Nafaa, a professor of political science and a prominent figure in the reform movement.
Hundreds of Saudi Shi'ites also peacefully demanded that Saudi troops return from Bahrain, and called for political rights and freedoms at home, demonstrators said.
The protests -- with riot police nowhere to be seen -- were held in the main Shi'ite Muslim center of Qatif, where demonstrators, some of them women, waved Bahraini as well as Saudi flags, and the nearby village of Awamiya.
Banners read "respect the rights to demonstrate" and "freedom of expression and opinion."
Saudi Arabia sent 1,000 troops last month to Bahrain, a Sunni Muslim monarchy, to help contain pro-democracy protests led by that Gulf Arab country's Shi'ite majority.
Heavy security prevented demonstrations after Friday prayers in the Omani city of Sohar, where protesters camped out for over a month before forces moved them out last week.
Checkpoints were set up across the city with dozens of armoured vehicles blocking access to protest areas. Residents' names were checked against a list and access to mosques was restricted, while a helicopter flew overhead, witnesses said.
(Reporting by Mohamed Sudam, Erika Solomon, Khaled al-Mahdital, Nick Macfie, Saleh Al-Shaibany, Mariam Karouny, Yara Bayoumy, Khaled Yacoub Oweis, Jason Benham and Suleiman al-Khalidi; writing by David Stamp; editing by Ralph Boulton)