Syrian security forces killed 20 people on Friday and protesters called on the Arab League to suspend Damascus's membership in response to continued violence, activists said.
Activists in Homs, which has suffered the highest death toll of any Syrian province since an uprising against President Bashar al-Assad broke out in March, said security forces killed nine civilians and one defecting soldier.
The other fatalities were in Hama, the old Roman city of Busra al-Sham in the southern Hauran Plain and in the northern province of Idlib, they said.
The people want (Syria's) membership to be suspended, shouted a crowd at a rally in the Deir Baalba district of Homs, appealing to the 22-member Arab League to act against Damascus when it meets in Cairo on Saturday, Internet footage of the rally showed.
Under an Arab League plan agreed on November 2, Syria pledged to pull the military out of restive cities, free political prisoners and start talks with the opposition.
Since then, security forces have killed more than 100 people in Homs, Human Rights Watch said in a report issued on Friday.
The systematic nature of abuses against civilians in Homs by Syrian government forces, including torture and unlawful killings, constitute crimes against humanity, the group said.
It called on the Arab League to suspend Syria, request the United Nations impose sanctions on those responsible for the violence and refer Syria to the International Criminal Court.
Assad, from the minority Alawite community which has held power for four decades in mainly Sunni Muslim Syria, has said he has used legitimate means to confront a foreign conspiracy to sow sectarian strife.
The official news agency said armed terrorist groups killed two security police and four civilians in the provinces of Homs, Hama and Idlib and explosive devices were dismantled in several areas across the country.
The agency quoted Syria's representative to the Arab League as saying Syria was serious in its commitment to the plan and that authorities have implement most of it.
Damascus invited the Arab League a month ago to send officials to Syria to have knowledge of the truth ... away from political unfairness and media falsehood, he said.
Syria blames armed groups for the violence and says 1,100 members of the security forces have been killed.
Syrian authorities have barred most foreign media from the country making it difficult to verify accounts of violence from activists and authorities.
In Homs on Friday, protesters waved the green, white and black flag used by Syria before the Baath Party seized power nearly 50 years go. Proud Homs! they shouted.
A YouTube video purportedly showed several teenagers in Busra al-Sham -- some throwing stones, others chanting Bashar you are betraying your people -- coming under automatic fire.
Another YouTube clip showed a boy lying on the asphalt with a blood-stained chest, murmuring as his friends urged him to say There is no god but God, as a last rite.
The violence has drawn condemnation from Western powers as well as neighbouring Turkey and some Arab states. But the Syrian leader has allies in the region and supporters at home.
Sayyed Hassan Nasrallah, leader of Lebanon's pro-Syrian Hezbollah movement, said on Friday some politicians in Lebanon were building hopes and dreams of Assad's overthrow.
I say to them: 'Put these bets to one side.' I also say to them: 'This bet will fail as all previous bets failed. Don't waste your time', he said in a televised speech.
Wary of chaos and an Islamist takeover if Assad leaves, Syria's Christian clerical establishment have also made public statements in support of Assad, although opposition to Assad family rule has historically included prominent Christians.
A Syrian archbishop told an Austrian newspaper in remarks published on Friday that everyone loves Assad and that he was still the best man to enact reforms.
The United Nations says more than 3,500 people have been killed in the crackdown on the protests, inspired by uprisings which have toppled autocrats in Tunisia, Egypt and Libya.
Alongside the mainly peaceful protests there have been increasing attacks on security forces by army defectors. Activists said at least 30 civilians and 26 soldiers were killed on Thursday. The daily reported death tolls this month have been some of the highest since the uprising erupted.
Arab states remain divided over how to deal with Syria and Saturday's meeting is not expected to bridge the gap.
Several countries oppose putting serious pressure on Assad and it looks unlikely that foreign ministers will freeze Syria's membership, officials due to attend the Cairo talks say.
Saudi Arabia leads a group of Gulf states including Qatar, Oman and Bahrain that are ready to increase the pressure on Assad, an ally of their rival Iran.
Diplomats say they are opposed by countries such as Yemen --in the grip of its own uprising; Lebanon -- where Syria's influence looms large; and Algeria, seen as more sympathetic to Assad and nervous about the message any intervention in Syria would send to its own population.
The United States and European Union have imposed sanctions on Syria's oil industry and several state businesses, forcing Damascus to curb oil production. Industry sources said oil majors Royal Dutch Shell and Total have slashed output in Syria.
Syrian oil represents less than 1 percent of daily global production but accounts for a vital portion of state earnings, which have been hit by the collapse of tourism revenues.
(Additional reporting by Dominic Evans and Laila Bassam in Beirut, Suleiman al-Khalidi in Amman, Emma Farge and Muriel Boselli in London; Editing by Janet Lawrence)