Opposition leaders have been pressing the League to suspend Syria's membership over the crisis, which the UN says has cost more than 3,500 lives since protests against President Bashar al-Assad erupted in mid-March.
Fifteen people, including an army deserter, were killed in Homs in the latest violence, the Syrian Observatory for Human Rights said.
Another civilian was killed near Idlib, in the northwest near Turkey, and five in Daraa. Three bodies were also found in Homs.
Also in Daraa, at least four soldiers were killed and 15 wounded in attacks on military roadblocks, the Observatory said.
The deaths in Homs came amid mass anti-regime rallies demanding the Arab League suspend Syria's membership in the pan-Arab body to sanction its brutal, eight-month crackdown on dissent.
Security forces broke up demonstrations in Al-Malaab, a main thoroughfare in Homs, but rallies relocated and mushroomed, engulfing eight neighbourhoods, the Observatory said.
The Observatory also reported the entry of tanks into the Idlib town of Sheikhun in the wake of "mass demonstrations" and "violent clashes" that led to the "retreat by security forces from government buildings."
In Damascus, there were security forces on the streets of Barzeh and posted snipers on rooftops, after a wave of arrests and deadly violence shook the neighbourhood.
One person was killed in the Damascus area.
And "security forces unleashed heavy gunfire to disperse demonstrations," in the eastern oil hub of Deir Ezzor.
Friday prayers have become a lightning rod for demonstrations in Syria, which each week adopt a new theme. This week they called for the Arab League to suspend Syria's membership.
The League, under international pressure to act after Syria failed to honour a peace deal and instead stepped up its brutal protest crackdown, held talks ahead of a meeting on Saturday to discuss the crisis.
Syria's envoy to the Arab League, Yussef Ahmad, presented a memorandum in which Damascus expressed its willingness to receive a pan-Arab delegation.
"This will help assess Damascus's commitment to the (Arab) plan and to unveil motives behind certain external and internal parties working for the failure of the Arab blueprint," the official SANA news agency said.
Meanwhile, Human Rights Watch (HRW), like protesters, urged the Arab League to suspend Syria's membership.
It accused Syrian government forces of "crimes against humanity" based on the systematic nature of abuses against civilians.
It said protesters were unarmed in most clashes, but that defectors from the security forces had intervened when the demonstrators came under fire from regime troops and militiamen.
Based on the accounts of 110 victims and witnesses, HRW said "violations by the Syrian security forces killed at least 587 civilians" in Homs and its province between mid-April and the end of August.
With their latest assault on the flashpoint city, at least another 104 people have been killed since November 2 when the regime agreed to the Arab League initiative to end the violence.
"Homs is a microcosm of the Syrian government’s brutality," said Sarah Leah Whitson, HRW's Middle East director.
"The Arab League needs to tell President Assad that violating their agreement has consequences, and that it now supports Security Council action to end the carnage," she said.
Under the deal, Damascus was to release those detained for protesting and withdraw military forces from towns and cities. It says it has already released more than 500 people.
Elsewhere, a Lebanese man's leg was blown off after he stepped on a mine planted hours earlier by Syrian troops along Lebanon's northern border, local and hospital officials said.
And strapped for cash after sanctions imposed by the European Union, Syria has stopped paying Shell and Total for their oil production in the country, the Financial Times reported.
-------------------------------------------------------------------------------