BEIRUT -- Hundreds of thousands of people took to the streets in cities across Syria Friday in a display of defiance to show an Arab League observer mission the strength of the opposition movement.
Despite the monitors' presence, activists said Syrian forces loyal to President Bashar Assad killed at least 22 people, most shot during anti-government demonstrations.
In a further attempt to appeal to the monitors, dissident troops who have broken away from the Syrian army said they have halted attacks on regime forces to reinforce the activists' contention that the uprising against Mr. Assad is a peaceful movement.
The rebel Free Syrian Army said it has about 15,000 army defectors.
Friday's crowds were largest in Idlib and Hama provinces, with about 250,000 people turning out in each area, according to an activist and eyewitness who asked to be identified only as Manhal because he feared government reprisal.
Other big rallies were held in Homs and Daraa provinces and the Damascus suburb of Douma, according to Rami Abdul-Raham, who heads the British-based Syrian Observatory for Human Rights.
The crowd estimates could not be independently confirmed because Syria has banned most foreign journalists from the country and tightly restricts local media.
The outpouring of demonstrators -- Friday's protests were the largest in months -- underscores protesters' wish to make their case to the foreign monitors and take advantage of the small measure of safety they feel they brought with them.
The Arab League monitors are the first that Syria has allowed into the country during the uprising, which began in March.
They are supposed to ensure the regime complies with terms of the Arab League's plan to end Mr. Assad's crackdown on dissent.
The United Nations says more than 5,000 people have died as the government has sought to crush the revolt.
Haytham Manna, a prominent Paris-based dissident and human rights defender, said the observers' presence has emboldened protesters to take to the streets in huge numbers.
"Whether we like it or not, the presence of observers has had a positive psychological effect, encouraging people to stage peaceful protests -- a basic condition of the Arab League peace plan," he said.
The orange-jacketed observers have been seen taking pictures of the destruction, visiting families of victims of the crackdown, and taking notes.
On Friday, they were within "hearing distance" from where troops opened fire on tens of thousands of protesters in the Damascus suburb of Douma, activist Salim al-Omar said. They later visited the wounded in hospital, he added.
The Arab League mission has met with skepticism over its makeup, its lack of numbers -- scheduled to increase from 60 to 150 -- and its reliance on government transport.
A first assessment by its leader that the situation was "reassuring" prompted disbelief in the West on Wednesday.
But that leader, Sudanese Gen. Mohamed Ahmed Mustafa al-Dabi, whom some link to war crimes in Darfur in the 1990s, said Friday the reports of his comments were "unfounded and not true," a mission statement said.
The monitoring teams have encountered problems that include hostility when they turn up under army escort, random gunfire, shouting mobs, and breakdowns in communications.
An Arab League member played down expectations for the mission, which has no peacekeeping mandate.
Even if its report turns out to be negative, it would not "act as a bridge to foreign intervention" but simply indicate "the Syrian government has not implemented the Arab initiative," the delegate told Reuters.
Omar Shaker, an activist and resident of the battered neighborhood of Baba Amr in Homs, said the observers were "laughable," often walking around with outdated cameras and without pens.
"Still, the bombardment and killings have decreased here in their presence. We see them as a kind of human shield, that's all," he said.
In Douma, up to 100,000 people protested Friday.
The Observatory, which relies on a network of activists on the ground, said the regime used nail bombs against protesters in Douma.
The report was confirmed by Douma activist al-Omar.
In another video, a huge crowd packed a main street in Homs, singing anti-Assad songs and dancing in unison.
Thousands turned out in the city of Idlib to welcome the observers, filling a large square, waving olive branches and flags, and chanting, "The people want the fall of Bashar."
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 popular support.