BEIRUT >> Shots rang out after the Syrian army sealed off the key port city of Banias on Sunday where anti-government protesters turn out, undaunted by the regime’s use of deadly force to quell more than three weeks of unrest.

Human rights groups said there were casualties, but the reports were not immediately confirmed. Syrian state-run television reported that a police officer was killed in an ambush by thugs near Banias, which is 185 miles northwest of the capital, Damascus.

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

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.

The government blames the violence on armed gangs rather than true reform-seekers and has vowed to crush further unrest.

Assad said 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.

Several human rights activists spoke to the AP on Sunday, citing Banias residents who fled the city.

Ammar Qurabi, head of Syria’s National Organization for Human Rights, said reports indicated that people had been killed and injured when security forces opened fire on a protest. Another activist, Mazen Darwish, said at least four tanks were deployed in the city, apparently to protect the oil refinery, which is the main point to export Syrian oil.

"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.

Syria’s National Organization for Human Rights said one person was wounded in Banias, but there were no details.

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.

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.