Masked gunmen dragged Syria's best-known political cartoonist from his car before dawn Thursday, beat him severely and broke both his hands as a warning to stop drawing just days after he compared Syria's president to Muammar Qaddafi, a relative and activists said.

Hospitalized with serious injuries, 60-year-old Ali Ferzat has become the most famous victim of the repression of Syria's five-month uprising. The attack on him was a stark reminder that no Syrian is immune to the crackdown.

"This is just a warning," the gunmen told Ferzat, according to a relative who asked that her name not be used for fear of reprisals. "We will break your hands so that you'll stop drawing."

The men then singed the artist's beard, put a bag over his head and dumped him on the side of the road.

The widely popular cartoonist, who works late into the night, left his studio at 4 a.m. Thursday, the relative and several activists familiar with the attack told The Associated Press.

A jeep with tinted windows soon started trailing him and cut him off on a Damascus street. Four masked gunmen dragged him out of his car, bundled him into the jeep and drove him to the airport road just outside Damascus, beating him and making threats all the while.

After news of the attack broke, online social networking sites exploded with angry postings.

"Assad's Syria is the burial ground of talent," read a posting on Twitter.

"Ali Ferzat, your innovation will stand in the face of their cowardice and hate," wrote Suheir Atassi, a prominent Syrian pro-democracy activist.

Pictures published on online forums Thursday showed the artist in a hospital bed with heavily bandaged hands and a bandage above his right eye.

Omar Idilbi, a spokesman for the Local Coordination Committees, an activist group that helps organize and track the uprising, blamed security forces for the attack, although Rami Abdul-Rahman, head of the London-based Syrian Observatory for Human Rights, said the identity of the attackers could not be confirmed.

Ferzat has said he had great hopes for Assad when he became president in 2000 after inheriting power from his late father. But in recent years Ferzat has become a vehement critic of the regime, particularly as the military launches a brutal crackdown on the country's protest movement.

This week, he published a cartoon on his website showing Assad with a packed suitcase, hitching a ride with a fleeing Qaddafi. Many of his cartoons directly criticize Assad, even though caricatures of the president are forbidden.

Ferzat's website, where he published his cartoons and satirical commentary, was inaccessible Thursday after the attack. "This account has been suspended," reads a message on the website, http://www.ali-ferzat.com/.

"There are two things in this life that cannot be crushed -- the will of God and the will of the people," Ferzat told the AP this month during a telephone interview from Damascus.

Ferzat benefited from Assad's moves to open up society in Syria during a period that came to be known as the Damascus Spring. Shortly after Assad inherited power from his father, he allowed Ferzat to publish the country's first private newspaper in decades.

The satirical weekly Al-Domari -- or The Lamplighter -- was an instant hit, with copies of each issue selling out a few hours after hitting the stands. It was soon shut down, however, as Assad began cracking down on dissent after the Damascus Spring quickly lost steam.

Human rights groups said Assad's forces have killed more than 2,000 people since the uprising against his autocratic rule erupted in mid-March, touched off by the wave of revolutions sweeping the Arab world.