A Swedish artist whose drawing of the Prophet Muhammad offended Muslims said Wednesday he hopes to get another chance to deliver a lecture on free speech that was interrupted by violent protests.But officials at Uppsala University said they doubted they would invite Lars Vilks again after police used pepper spray and batons to help him escape a furious crowd Tuesday."It's nothing that we're discussing right now, but it's not very likely given how it turned out here," university spokeswoman Anneli Vaara said.While Vilks escaped the incident with broken glasses and a bit of a shock, he said it raised concerns about the freedom of expression at Sweden's oldest and most prestigious institute of higher learning."What you get is a mob deciding what can be discussed at the university," Vilks told The Associated Press, adding he was ready to repeat the lecture if re-invited."I'm ready to go up again," he said. "This must be carried through. You cannot allow it to be stopped."The 53-year-old artist has faced numerous threats over his 2007 sketch of Muhammad with a dog's body. Earlier this year US investigators said he was the target of an alleged murder plot involving Colleen LaRose, an American woman who dubbed herself "Jihad Jane," and who now faces life in prison. She has pleaded not guilty.Vilks' Web site appeared to have been exposed to a hacker attack on Wednesday. Instead of his regular blog there was a message saying the site had been hacked and with links to information about the Prophet Muhammad.Witnesses said the violence Tuesday broke out a few minutes into Vilks' lecture about the limits of artistic freedom, when he showed a film by an Iranian artist about Islam and homosexuality. A young man leaped from his front-row seat and tried to attack Vilks, police and the artist said.Vilks initially believed he was head-butted by the man, but said he later understood he had collided with plainclothes police officers who intercepted the attacker and then briskly evacuated Vilks from the room."This was the first time I've experienced a physical assault," Vilks said. "It was a bit of a shock."A video of the incident showed agitated police officers clashing with protesters at the front of the lecture hall. A female police officer used pepper spray to subdue a young man, and another youngster was wrestled to the ground. Some protesters were shouting "God is great" in Arabic.Uppsala police spokesman Jonas Eronen said two officers sustained minor injuries.The attacker was detained on suspicion of attempted assault but was later released, he said. Two others — a man and a woman — were also released after questioning and could face charges of using violence against police. All suspects were in their late teens, Eronen said.Vaara, the university spokeswoman, said the lecture had been open to the public and the suspects were not believed to be students, though she added she wasn't sure about that.The incident was condemned by Swedish newspaper editorials calling it an attack on the freedom of speech, and in more moderate terms by the Scandinavian country's leading politician."It shows that there are tensions in this discussion, which I've had to follow for years," Prime Minister Fredrik Reinfeldt told reporters in Stockholm. "I take it very seriously. There is a risk that tensions form between individuals and the Swedish society, which is something we don't want."Helena Benauouda, the head of Sweden's Muslim Council, an umbrella group for Muslim organizations, declined comment, saying she didn't have enough information about the incident.Vilks depicted Muhammad more than a year after 12 Danish newspaper cartoons of the prophet sparked furious protests in Muslim countries in 2006. Images of Muhammad, even favorable ones, are considered blasphemous by many Muslims.A Swedish newspaper printed Vilks' drawing, leading to further protests, and revived a heated debate in the West and the Muslim world about religious sensitivities and the limits of free speech.