Some of the Palestinian reaction to Israeli policy in the West Bank and Gaza Strip has consisted of non-violent protest, primarily in and near the village of Bil'in. Groups such as the Palestinian Centre for Rapprochement, which works out of Beit Sahour, formally encourage and organize non-violent resistance. Other groups, such as the International Solidarity Movement openly advocate non-violent resistance. Some of these activities are done in cooperation with internationals and Israelis, such as the weekly protests against the Israeli West Bank Barrier carried out in villages like Bi'lin, Biddu and Budrus. This model of resistance has spread to other villages like Beit Sira, Hebron, Saffa, and Ni'lein. During the Israeli re-invasion of Jenin and Nablus, "A Call for a Non-violent Resistance Strategy in Palestine" was issued by two Palestinian Christians in May 2002.