The United States Wednesday condemned an arson attack on an old mosque in Jerusalem earlier that day, calling on both sides show restraint and restore calm."We condemn in the strongest possible terms today's burning and vandalizing of the mosque in Jerusalem," State Department spokesperson Victoria Nuland said of the attack.RELATED:Analysis: Time to create deterrenceEditorial: Fighting extremismOn old mosque on in Jerusalem was burned and covered with anti-Arab graffiti early on Wednesday morning in the latest price tag attack by right-wing extremists angry at government policies. The mosque, on Strauss Street near downtown Jerusalem, is no longer in use.Overnight, extremists broke into the mosque and tried to set it on fire. The mosque was badly burned by not structurally damaged. The walls were covered with graffiti, including “A good Arab is a dead Arab,” “price tag,” “Muhammad is dead” and “Muhammad is a pig.”The extremists also wrote “Mitzpe Yitzahar,” referring to an illegal West Bank outpost that could be demolished along with parts of Ramat Gilad in the coming days.Officials were quick to condemn the attack. Jerusalem mayor Nir Barkatvisited the mosque early on Wednesday morning. “We have zero tolerance for any type of violence,” he said.Three fire crews responded to the early morning blaze, and encountered a fire raging in one of the western rooms of the mosque. The fire was quickly put out, but caused significant smoke damage, and some of the walls were blackened. Fire investigators said that material gathered from the site of the fire points to arson. Police and the Shin Bet opened a joint investigation.