Dozens of people have been injured in clashes in the Syrian port of Baniyas, where 13 people were killed on Saturday, residents say.
One area is surrounded by army vehicles and gunfire is ongoing, they say.
Rights groups say hundreds of people have been arrested, including several students who took part in a rare rally at Damascus University on Monday.
In the coastal city of Baniyas, meanwhile, Foreign Media Agencies said another 22 people were arrested on Monday, as funerals were held for the four people who died when security forces opened fire on protesters over the weekend.
The government said nine soldiers died in the clashes and another 18 were injured in Saturday’s clashes.
Nine soldiers, including two officers, were also killed and several wounded when their patrol was ambushed outside Banias, a coastal city 280 kilometres northwest of Damascus, the official SANA news agency said.
Parts of the city remain under lockdown on Tuesday, residents have told the BBC.
One witness says the village of Bayda is surrounded by army vehicles. He says dozens of people have been injured in clashes with security forces, and that soldiers are preventing ambulances from getting into the town.
Earlier on Tuesday, Human Rights Watch (HRW) accused Syrian security forces of preventing medics from reaching wounded protesters when clashes erupted at anti-government demonstrations last week.
The army had sealed off the city as hundreds of protesters gathered, undaunted by the government’s use of force to quell more than three weeks of unrest, witnesses said. State television reported that nine soldiers were killed in an ambush near the city.
Details were sketchy because telephone lines, electricity and Internet access were apparently cut to most parts of Banias. Army tanks and soldiers circled the city, preventing people from entering.
But one witness, reached by telephone, told NY Times that hundreds of protesters had assembled near al-Rahman Mosque when security forces and armed men in civilian clothes opened fire. The names of the dead were read out on the mosque’s loudspeakers.
Syrian human rights activists have reported a country-wide wave of arrests focused on protest participants and organisers.
Syrian students on Monday staged a rally, rare for Damascus, to express solidarity with protesters killed over the weekend. DP