The US has demanded that the government of Syrian President Bashar al-Assad stop brutalising peaceful opponents, citing in particular, what it called a "targeted, brutal attack" on Syria's most popular political cartoonist.
Ali Ferzat was attacked after he left his studio early on Thursday and was beaten by masked gunmen who broke his hands and dumped him on a road outside the Damascus airport.
Ferzat's brother Asaad told Al Jazeera that his brother was kidnapped at 5am by five gunmen from outside his home and taken to the airport road.
"He was savagely beaten, they broke his fingers and told him not to satirise Syria's leaders," Asaad said.
Ferzat remembers the gunmen telling him that "this is just a warning," as they beat him, a relative told The Associated Press news agency.
Ferzat, 60, who is also a longtime human rights advocate, earned international recognition and the respect of many Arabs with stinging caricatures that infuriated leaders including Iraq's Saddam Hussein, Libya's Muammar Gaddafi and, particularly in recent months, Syria's Assad family.
He drew cartoons about the uprising and posted the illustrations on his private website, providing
comic relief to many Syrians who were unable to follow his work in local newspapers because of a ban on his drawings.
His illustrations grew bolder in recent months, with some of his cartoons directly criticising Assad, even though caricatures of the president are forbidden in Syria.
This week, he published a cartoon showing Assad with a packed suitcase, frantically hitching a ride with a fleeing Gaddafi. Another drawing showed dictators walking a long red carpet that leads them, in the end, to a dustbin.
'Campaign of terror'
Victoria Nuland, US state department spokeswoman, said in a statement after Ferzat's attack: "The regime's thugs focused their attention on Ferzat's hands, beating them furiously and breaking one of them, a clear message that he should stop drawing."
In her statement, Nuland said: "Many other moderate activists who oppose violence have been jailed for speaking out against the regime.
"While making empty promises about dialogue with the Syrian people, the Assad regime continues to carry out brutal attacks against peaceful Syrians trying to exercise their universal right to free expression.
"We demand that the Assad regime immediately stop its campaign of terror through torture, illegal imprisonment and murder," Nuland added.
In-depth coverage of escalating violence across Syria
The remarks came as activists reported at least eight people killed by security forces in street protests overnight, a day after violence in which 11 civilians and eight soldiers were killed.
Human rights groups also reported Assad's forces have killed more than 2,000 people since the uprising against his autocratic rule erupted in mid-March.
Despite the crackdown, anti-government protests are ongoing across the country.
Possible UN sanctions
Amid the increasing violence, the European Union and the United Nations announced plans for more sanctions against Assad's government.
EU governments are likely to adopt an embargo against imports of Syrian oil by the end of next week, an EU diplomat said on Wednesday.
The Security Council scheduled closed consultations on Thursday on their draft resolution that would impose an arms embargo on Syria, an asset freeze on Assad and key members and companies associated with his regime, and a travel ban on 21 individuals.
Diplomats said Russia and China, both with close ties to Damascus, boycotted the meeting.
Vitaly Churkin, the Russian UN ambassador, hinted on Wednesday that he would veto the resolution, saying the council should use dialogue to persuade Syria to end its violent crackdown on protesters.
Calls to Russian and Chinese UN missions seeking comment were not immediately returned.