An American demonstrator seriously injured in clashes between protesters and IDF soldiers is in stable condition, a spokesperson for the Sheba Medical Center at Tel Hashomer said on Sunday. Tristan Anderson, 38, of Oakland, California, was hit in the head by a tear gas canister during a protest against the West Bank security barrier in Nil'in on Friday and underwent surgery at the hospital, near Tel Aviv. Anderson is on a respirator but in stable condition, the spokeswoman said on condition of anonymity because of the issue's sensitivity. The protest took place in the West Bank town of Nil'in, near Ramallah, where Palestinians and international backers frequently gather to demonstrate against the security barrier. The IDF says the area where the protests take place is a closed military zone off-limits to demonstrations. About 400 protesters turned out in Nil'in on Friday, according to the IDF. Some of them hurled rocks at troops, who used riot gear to quell the unrest, it added, without elaborating. Ulrika Jenson, an International Solidarity Movement activist, said troops fired tear gas canisters into the crowd from a hill above. "Tristan was hit and fell to the ground," Jenson was quoted as saying in an ISM statement. "He had a large hole in the front of his head, and his brain was visible." In 2003, another ISM activist, 23-year-old American Rachel Corrie, was crushed to death in Gaza by an Israeli bulldozer as she tried to block it from demolishing a Palestinian home. The driver said he didn't see her, and the IDF ruled her death an accident. Jpost.com staff contributed to this report.