A young girl and six soldiers were among 21 Syrians killed on Thursday as security forces pressed a crackdown on protests and in clashes between troops and army deserters, a human rights group said.
The deadly clashes came as protest organisers called for nationwide demonstrations on Friday to demand the Arab League suspend Syria's membership in the pan-Arab group.
The Arab League, under international pressure to act after Syria failed to honour its peace plan and stepped up the brutal protest crackdown, is to hold talks on Friday ahead of an extraordinary weekend meeting on the crisis.
On the ground on Thursday, an eight-year-old girl was among 11 civilians killed by security forces in the besieged central city of Homs, said the Syrian Observatory for Human Rights.
The bodies of another five missing people were also found in the Homs region, the Observatory said in a statement.
"Security forces arrested three wounded people in a private hospital" in Homs, and several others were detained in Jassem, in southern Daraa province, the Observatory added.
In the northwestern province of Idlib, near the Turkish border, four civilians were killed during raids by the security forces, said the Britain-based watchdog.
Also in Idlib, "at least four soldiers in the regular army were killed at dawn in an attack, headed by armed men -- probably deserters -- on a military checkpoint in Has region, near Maaret al-Numan town," said the Observatory.
Early on Thursday, in Jabal al-Zawiya, people began a general strike, responding to protesters there, while security forces tried to force them to open closed shops, said the same source.
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In eastern Syria, two soldiers, one an officer, were killed and five soldiers wounded in another attack on a military checkpoint, east of Deir Ezzor.
And in Harasta, near Damascus, clashes took place between the military and presumed deserters.
Another protest group, the General Commission of the Syrian Revolution, called for Thursday to be a "day of general strike in Syria to support Homs," where security forces have killed dozens of civilians in a few days.
The strike call was observed in several cities, video footage posted on YouTube showed.
In the Damascus area of Barze, a huge deployment of security forces moved in and arrested several people. The previous night six people were killed during an operation to crush protests.
"Hidden gunmen have been posted on high buildings in Barze where a major protest is underway," the Observatory said.
On Wednesday, efforts to crush anti-regime protests resulted in 16 new civilian deaths, the Observatory said.
According to the United Nations, more than 3,500 people have now been killed in Syria since protests against Assad began in March.