Seven Israeli Jews were injured after they defied Israeli military orders to try to reach a holy site in the West Bank city of Nablus this morning.
The sources said one of the Israelis was critically injured when gunmen fired at their vehicle near Joseph's Tomb - believed by some to be the burial site of the biblical patriarch.
"All the wounded have been evacuated to hospital and the defence forces are carrying out a search in the area," a security source said. "They had not asked for permission to visit the site."
Palestinian residents of Nablus said the Israeli army had moved in to seal off the area of the shooting.
The army bans Israelis from visiting areas meant to be under Palestinian control. Visitors to Joseph's Tomb have required military escorts since the start of a Palestinian uprising three years ago. But some people try to make it by themselves to pray there.