SAN FRANCISCO -- Politics turned violent on the streets of San Francisco Thursday evening when a supporter of Sen. Barack Obama was slashed in the face by someone with clearly different opinions.

The incident occurred just after 6 p.m. when the victim, who had a permit, was working a stand in support of Obama for president at Fifth and Market streets, according to police.

Another man approached the victim and began to argue with him, police said. The suspect left but returned with a knife and allegedly stabbed the victim in the face.

Two officers were nearby and one was able to take the suspect into custody while the other transported the victim to the hospital with non-life threatening injuries, police said.