At least 32 people have been reported killed during fresh protests against the Syrian government, as hundreds of thousands of demonstrators flooded streets across the country.
Activists said the deaths on Friday came as protesters, emboldened by the presence of Arab League observers in the country, took to the streets after noon Muslim prayers.
The UK-based Syrian Human Rights Observatory said more than half a million people turned out for the largest demonstrations in months.
Al Jazeera's Dorsa Jabbari, reporting from Beirut in neighbouring Lebanon, said the demonstrations were taking place in 18 different provinces across Syria.
"One of the biggest demonstrations is near the capital, Damascus. Activists have called on all residents to try and reach the centre of their cities. In Damascus ... they are being met by security forces who have used tear gas, according to many of the residents nearby," she said.
"We know that large demonstrations are also under way in the city of Hama, [in] Homs, as well as [in] Idlib, where we've seen images of observers themselves along with the demonstrators in the midst of it all."
Omar Hamza, a witness to the clashes between security forces and demonstrators in the Damascus suburb of Douma on Friday, said government forces shot at protesters who gathered at a mosque in the city.
"More than 100 people are injured right now," he told Al Jazeera. "It is a very bad situation in Douma today."
Hesitant to speak
The violence comes as the Arab League observer team in Syria continues its mission aimed at determining whether President Bashar al-Assad is implementing a peace plan to end the violence.
Our correspondent said protesters on Friday were eager to show the observers the situation on the ground and have their stories heard, but some residents were more hesitant to speak.
In-depth coverage of escalating violence across Syria
"[The observers] are being followed by Syrian forces as part of the agreement, so they are responsible for their safety. So some residents don't feel they have the freedom to speak in front of Syrian authorities in front of the observers," she said.
Syrian activists called on Thursday for the removal of the head of the Arab League monitoring team in a new blow to the credibility of the mission.
The opposition has condemned the observers' presence as a farce to enable Assad to buy time and avoid more international censure and sanctions.
The 60 Arab League monitors are the first set of observers allowed in to the country during the nine-month uprising.
Their remit is to ensure that the government is complying with the terms of the regional bloc's plan to end the crackdown on protests.
Syrian activists, however, doubt Arab monitors are getting the access they need to be able to give a fair assessment of the violence that the UN estimates has left more than 5,000 people dead.
A member of the observer team told Al Jazeera the situation in Syria was "very dangerous".
The official, who declined to be named, said there was constant shelling in the city of Homs with some areas under control of the Free Syrian Army, an umbrella group of armed anti-government fighters.
|Observers plan to visit protest hubs in the country
The source said he believed the Arab League mission was certainly going to fail.
Speaking to Al Jazeera, Hadi Abdullah, an activist in Homs, said that monitors witnessed the crackdown on protests, but he was suspicious on how they would report it.
"The observers saw a lot of violence in the city. They saw how security forces shoot at protests. They also saw the bodies of dead people," Abdullah said.
"The monitors also saw destruction in the city. One of the observers asked residents of Bab Amr neighbourhood ‘How can you live in this place?'"
International diplomats from China, Russia and the US have urged Syria's government to facilitate the observer mission.
The Arab League plan, endorsed by Syria on November 2, calls for the withdrawal of the military from towns and residential districts, a halt to violence against civilians and the release of detainees.
The Syrian government says most of the violence has been perpetrated by "armed terrorist groups" that are working against the government.