Syrian President Bashar Assad's security forces opened fire on pro-democracy protesters across the country Monday, reportedly killing 13 in the coastal town of Jabla and another five in the southern town of Daraa.

Security forces backed by armored vehicles entered Daraa overnight and opened fire, a resident told Al Jazeera television Monday. Eight tanks were deployed in the old quarter of Daraa, a witness said, adding that several bodies were lying in the main street.

Open gallery view Syrian anti-government protesters carry banner in Arabic that reads "Daraa is our torch, Douma is our model," April 22 2011. Credit: AP

A witness in Daraa said snipers on government buildings and security forces in army fatigues had been shooting at random at houses since tanks moved in just after dawn prayers.

"People are taking cover in homes. I could see two bodies near the mosque and no one was able to go out and drag them away," the witness said.

Activists on social media posted footage of what they said were troops firing early Monday throughout Daraa. The sound of heavy gunfire punctuates the footage, as well as the labored, frightened breathing of the activist filming the footage.

The activist repeats the date, the location and says: "The army forces are entering Daraa. They are shelling the city of Daraa."

The video could not be independently verified and all witnesses spoke on condition of anonymity for fear of reprisals. Syria has banned nearly all foreign media and restricted access to trouble spots since the uprising began, making it nearly impossible to get accurate assessments of the situation on the ground.

Syria forces appear to planning a major security operation, closing off all Syrian land border crossings with neighboring Jordan on Monday.

A senior diplomat in the Jordanian capital confirmed that the two main Syrian crossings at Daraa and Nassib on the Syrian side were closed to traffic.

An official told Reuters the "timing is related to what appears to be a major security operation that is taking place right now".

The Syrian Observatory for Human Rights reported on Monday that pro-Assad forces shot dead at least 13 civilians Jabla.

The security forces and gunmen loyal to Assad deployed in the old Sunni quarter of Jabla on Sunday after a pro-democracy protest in the town the previous night, rights campaigners in contact with Jabla said.

A human rights campaigner reported that Syrian forces were continuing a brutal crackdown Monday, storming the Damascus suburb of Duma, shooting at unarmed civilians and arresting residents.

Civilians had been wounded in the shooting, an activist said.

"There are injured people. Scores have been arrested. The security [forces] are repeating the same pattern in all the centers of the democratic uprising. They want to put down the revolution using the utmost brutality," the rights campaigner told Reuters from Damascus.

The campaigner said all telecommunications with Duma had been cut, but one activist managed to escape the suburb after the attack began at dawn and report on the situation.

Despite Assad's caoncellation of decades-long emergency laws, his forces have continued to clash with protesters, killing more than 100 Syrians on Friday in the most brutal crackdown since the pro-democracy protests began some six weeks ago.

Syrian security forces detained dozens of opposition activists and protesters in raids on Sunday, yet another indication that Assad has little intent of relinquishing his authoritarian rule.