Syrian security forces and pro-government gunmen killed four protesters Sunday in the port city of Banias after the army sealed off the city as hundreds of protesters gathered, undaunted by the regime's use of deadly force to quell more than three weeks of unrest, witnesses said.

Details were sketchy because telephone lines, Internet access and electricity apparently were cut to most parts of the city. Army tanks and soldiers circled the city, preventing people from entering.

But one witness, reached by telephone, said hundreds of protesters had gathered near the al-Rahman mosque when security forces and armed men in civilian clothes opened fire on them. The names of the dead were read out on mosque loudspeakers.

He said dozens of people were wounded, but most of them asked to be treated at a small clinic instead of at the main hospital, which was under the control of the feared security forces.

Like most eyewitnesses who spoke to The Associated Press, he requested anonymity for fear of reprisals from the government. Several other human rights activists, also citing witnesses, reported shooting in Banias on Sunday.

"There are demonstrations throughout the city and people are chanting against the regime," said Haitham al-Maleh, an 80-year-old lawyer and longtime rights activist who spent years as a political prisoner in Syria.

The accounts could not be independently confirmed. The government has placed severe restrictions on news coverage and many journalists — including from The Associated Press — have been ordered to leave the country.

Protests erupted in Syria more than three weeks ago and have been growing steadily every week, with tens of thousands of people calling for sweeping reforms in President Bashar Assad's authoritarian regime.

More than 170 people have been killed, according to human rights groups.

The government blames the violence on armed gangs rather than true reform-seekers and has vowed to crush further unrest. On Sunday, the state-run news agency said thugs killed a police officer in an ambush near Banias, which is 185 miles (300 kilometers) northwest of the capital, Damascus.

Assad also Sunday that the country is "moving ahead on the road of comprehensive reforms," the state-run news agency SANA said. In recent weeks, Assad has answered the protesters with both force and limited concessions that have failed to appease an emboldened movement inspired by the Arab uprisings in Tunisia and Egypt.

A key demand of protesters is an end to a decades-old emergency law that gives the regime a free hand to arrest people without charge.

But Assad has stopped well short of the protesters" demands. Instead, he has promised to form committees to look into reform. Other gestures include granting citizenship to thousands of Kurds, the country's long-ostracized minority, and sacking his Cabinet. Firing the government was largely symbolic, however, as the real power in Syria is concentrated around Assad and a tight coterie of family and advisers.

Also Sunday, the caretaker Syrian government eased foreigner's access to real estate in what appeared to be an attempt to attract foreign investment.

But those gestures have failed to appease a growing movement that is raising the ceiling on its demands for concrete reforms and free elections.

Much of the most serious violence has been concentrated in the drought-parched southern city of Daraa — where some 25 people were killed Friday — and the Mediterranean port city of Latakia.

Twelve people were killed in Latakia two weeks ago, bringing the unrest to an area with strong historical ties to Assad's minority Alawite sect, which is an offshoot of Shiite Islam.

Like Latakia, Banias has a potentially explosive mix of religious groups and sects. It also has a major oil refinery, which is the main point of export for Syrian oil.