As the manhunt continues for the terrorist who killed Israeli father of six Raziel Shevah in Samaria earlier this week, Israeli security forces are bracing for violence.

Israeli forces surrounded the Palestinian city of Nablus and nearby villages overnight Thursday, arresting 18 wanted Palestinians across the West Bank as part of efforts to apprehend the shooter who killed Shevah.

Security checkpoints at the entrances and exits to Nablus as well as its environs remained in place on Friday as the search for Shevah’s shooter was ongoing. On Thursday, a 16-year-old Palestinian was killed in a clash in the village of Bureen, near Nablus, the Palestinian health ministry said. An IDF spokesperson said troops searching the area for suspects had come under attack from “a massive barrage of rocks” and that troops had fired at the main instigator.

Israeli defense officials voiced concern that the heightened military presence in the area could lead to friction with local residents. Another Palestinian was killed Thursday near the border with Gaza when Palestinian rioters threw stones at Israeli troops. The IDF spokesperson said violent clashes had erupted at two locations along the Gaza border, involving some 50 rioters hurling rocks and rolling burning tires, endangering the troops. The Israeli soldiers responded with warning shots followed by directed fire, according the spokesperson.