BEIRUT -- Hundreds of thousands of Syrians poured into the streets across the nation Friday in the largest protests in months, shouting for the downfall of the regime in a defiant display invigorated by the presence of Arab observers, activists said.
Despite the presence of the monitors, activists said Syrian forces killed at least 19 people, most of them shot during anti-government protests.
Rami Abdul-Raham, who heads the British-based Syrian Observatory for Human Rights, said the crowds were largest Friday in Idlib and Hama provinces, with 250,000 people each. Other massive rallies were held in Daraa province and the Damascus suburb of Douma, he said.
The ongoing violence in Syria, and new questions about the human rights record of the head of the Arab League monitors, are reinforcing the opposition's view that Syria's limited cooperation with the observers is nothing more than a ploy by President Bashar Assad's regime to buy time and forestall more international condemnation and sanctions.
There is broad concern about whether Arab League member states, with some of the world's poorest human rights records, were fit for the mission to monitor compliance with a plan to end to the crackdown on political opponents by security forces. The United Nations says some 5,000 people have been killed in the government campaign since March.
One of Assad's few remain allies, Russia, voiced its approval of the observer mission so far, saying the situation was "reassuring." At the same time, a group of dissident soldiers who joined the opposition announced it has halted attacks on regime troops since the observers arrived in a bid to avoid fueling government claims that it is facing armed "terrorists" rather than peaceful protesters.
Despite skepticism over the Arab League mission, it has energized the protest movement, with tens of thousands turning out this week in cities and neighborhoods where the observers are expected to visit.
The huge rallies have been met by lethal gunfire from security forces, apparently worried about multiple mass sit-ins modeled after Cairo's Tahrir Square. In general, activists say, security forces have launched attacks when observers were not present. But there have been some reports of firing on protesters while the monitors were close by.
The Local Coordination Committees, an activist coalition, said at least 130 people, including six children, have been killed in Syria since the Arab observers began their one-month mission on Tuesday.
The nearly 100 Arab League monitors are the first Syria has allowed in during the uprising, which began in March. They are supposed to ensure the regime complies with terms of the League plan to end President Bashar Assad's crackdown on dissent.
The plan, which Syria agreed to on Dec. 19, demands that the government remove its security forces and heavy weapons from cities, start talks with the opposition and allow human rights workers and journalists into the country. It also calls for the release of all political prisoners.
Pro-Assad groups turned out for rallies in Damascus and several other cities, waving portraits of the president, in an apparent bid to show the regime has public support during the observer visit. On Friday, Russia's Foreign Ministry said an initial assessment by Arab League observers in Syria was "reassuring." Moscow is one of Syria's few remaining allies following more than nine months of violence.
"Moscow appraises with satisfaction the real beginning of the Arab League activities in Syria," the Foreign Ministry said in a statement. The ministry noted that the Sudanese general who heads the mission visited the restive city of Homs.
"The situation there is reassuring, clashes have not been recorded," the statement said.
Also Friday, the rebel Free Syrian Army said it has stopped its offensive against government targets during a month-long mission by Arab Legue monitors, saying it wants to expose how the regime is killing peaceful protesters.
The leader of the FSA, breakaway air force Col. Riad al-Asaad, said his troops have halted attacks since the observers arrived. The government insists terrorists and gangs are driving nine months of crisis in Syria.
"We stopped to show respect to Arab brothers, to prove that there are no armed gangs in Syria, and for the monitors to be able to go wherever they want," al-Asaad told The Associated Press by telephone from his base in Turkey.
"We only defend ourselves now. This is our right and the right of every human being," he said, adding that his group will resume attacks after the observers finish their mission.
The Free Syrian Army says it is comprised of some 15,000 army defectors who abandoned the regime during the uprising. The group has claimed responsibility for attacks on government installations that have killed scores of soldiers and members of the security forces.
On Friday, activists said security forces fired on protesters in the southern province of Daraa, Hama province in central Syria and elsewhere. In the central city of Homs, six people who were reported missing Thursday were confirmed dead Friday.
Another four were reported killed in the town of Talkalakh, near the border with Lebanon, in an ambush by government troops. It was not immediately clear why they were killed as the victims were not believed to be protesting at the time, activists said.
In total, 19 people were reported killed Friday.
In Washington, State Department spokeswoman Victoria Nuland on Thursday expressed concern that violence was continuing in Syria despite the presence of the monitors.
She said the monitors were providing "some space for public expression," citing videos on YouTube of a large democracy rally in Idlib, but insisted that Assad's regime needed to do more.
"It's not only a matter of deploying the monitors," she added. "It's a matter of the Syrian government living up to its commitments to withdraw heavy weapons from the cities; to stop the violence everywhere, which clearly has not happened; to release all political prisoners."