During the celebration, demonstrators held signs stating "Unity is our strength" and "Unity = Liberty" in an event marking the signing of an agreement in Cairo reconciling Hamas and Fatah and reuniting the West Bank and Gaza under a single government once the agreement is put in place.
Local committee spokesman Mohammad Ayyad Awad said Israeli soldiers fired tear gas and attacked demonstrators with stun grenades, rifle butts and batons.
Soldiers tried to arrest head of the anti-wall committee Yousef Abed Al-Hamid Abu Maria, 36, who owns land confiscated by the illegal Karmi Tzur settlement. Organizers said soldiers twisted Abu Maria's arm and wrist until it broke in two places.
Abu Maria with a broken arm, in a photo provided by the local popular committee [MaanImages/HO]
Forces released Abu Maria when they realized he was seriously injured, a statement from the popular committee said, adding that he was taken to hospital in Hebron and treated for a broken wrist and sprained leg.
Awad said committee secretary Ahmad Khalil Abu Hashem, 42, his 12-year-old son Hamza and coordinator Abed Abu Maria, 33, were beaten by soldiers and sustained bruises.
Several journalists were also attacked, Awad said, adding that Israeli forces declared the area a closed military zone.
The area is also a site of weekly protests, which see locals and international activists march, demanding the end to Israel's confiscation of land from Beit Ummar and Halhul to build illegal Jewish-only settlements.
Israel's supreme court ruled in 2006 that farmers whose land was confiscated by Karmi Tzur settlement, including those attacked on Saturday, should be allowed to access their land with permits from Israeli authorities.
Since 2006, Israeli authorities have not issued any permits, Awad noted.
Also on Saturday, Israeli soldiers and settlers attacked two elderly farmers working on their land near the illegal Beit Ayin settlement, Awad said.
He identified the farmers as 85-year-old Abdallah Suleibi and his brother Hammad, 75.