Syrian security forces opened fire on protesters in several parts of the country on Friday, killing at least eight people and wounding scores, while masked gunmen burst into an apartment in the predominantly Kurdish northeast and shot dead one of Syria's most prominent opposition figures.
Another leading opposition figure was beaten up by pro-government gunmen and rushed to a hospital in Damascus, activists said.
The slaying of Mashaal Tammo, a 53-year-old former political prisoner and a spokesman for the Kurdish Future Party, was the latest in a string of targeted killings in Syria as the country slides further into disorder, seven months into the uprising against President Bashar Assad.
Tammo, killed by unknown gunmen in the city of Qamishli, was also a member of the executive committee of the newly formed Syrian National Council, a broad-based front bringing together opposition figures inside and outside the country in an attempt to unify the deeply fragmented dissident movement.
Tammo's son and another member of the Kurdish Future Party were wounded in the attack, said Omar Idilbi, a spokesman for an activist group called the Local Coordination Committees.
Qamishli erupted in protests as thousands of outraged people took to the streets and swarmed the hospital were Tammo was taken, many of them shouting "Azadi," the Kurdish word for freedom, said Mustafa Osso, a Kurdish lawyer and activist from the city.
Tammo, a vocal regime opponent, had been instrumental in organizing anti-government protests in Qamishli in recent months.
"The regime is responsible for this killing," Osso said. "Mashaal had no enemies, his only crime was that he was a political activist and a supporter of the revolution," he added.
The killing could spark violent protests in the Kurdish region at a time when Syria's security forces already have their hands full in trying to stamp out dissent across much of the rest of the country. Kurds _ the largest ethnic minority in Syria _ make up 15 percent of the country's 23 million people and have long complained of neglect and discrimination.
Assad granted citizenship in April to stateless Kurds in eastern Syria in an attempt to address some of the protesters' grievances.
Tammo's assassination was similar to other recent targeted killings in Syria by unknown gunmen, raising concerns the country might be sliding toward civil war. The most recent was the assassination of the son of Syria's top Sunni cleric, who died in a hail of bullets outside the university where he studied earlier this week.
Several academics and physicists have also been shot dead by gunmen in the past month, most of them in the country's restive central and northern regions.
In what has become a weekly ritual of protests and violence, security forces opened fire at Friday rallies by tens of thousands of marchers in the streets of several Syrian cities, towns and villages. At least eight people were killed and scores were wounded, according to various activists.
The Syrian Observatory for Human Rights said at least four people were killed and 25 were wounded in the central city of Homs, Syria's third largest city. It also reported intense shooting in the eastern city of Deir el-Zour near the border with Iraq, and the Damascus suburb of Douma.
In Douma, the Observatory said at least three people were killed and several were wounded, while five were wounded in the northern town of Maaret al-Numan.
Osso said one person was also killed in the town of Zabadani near the border with Lebanon.
Meanwhile, Riad Seif, a former lawmaker who became a leading opposition figure and outspoken critic of Assad's regime, was beaten up outside a mosque in the central Damascus suburb of Midan, according to two Syria-based activists.
Seif, who suffers from cancer and had been detained earlier this year, was rushed to hospital after the beating, said Osso and Idilbi. Amateur video posted on the Internet showed Seif at the hospital, with bruises to his back and hands.
In Washington, State Department spokeswoman Victoria Nuland lamented the "absolutely gruesome" online footage of Seif being attacked, and the separate shooting that claimed the life of Tammo.
"Both of these guys were opposition advocates, who advocated nonviolence and were peaceful themselves," Nuland told reporters.
The Local Coordination Committees also reported heavy shooting in the village of Jassem in the southern province of Daraa, where the uprising against Assad's regime began seven months ago.
Since mid-March, the Syrian government crackdown has left at least 2,900 people dead, including members of security forces, according to the U.N.'s human rights office. The figure rose by at least 200 since the beginning of September.
AP writers Zeina Karam in Beirut and Bradley Klapper in Washington contributed to this report.
Bassem Mroue can be reached on http://twitter.com/bmroue