Save the Jordan Valley campaign coordinator Fathi Ikhdeirat said Israeli authorities, accompanied by border guards, began tearing down structures and handing down stop-work orders to residents.
He described the move as an attempt "to clear the area of its indigenous people and include it into Israel and called on international human rights groups to intervene to bring the demolitions to a halt.
A spokesman for Israel's Civil Administration did not immediately return a phone call seeking comment.
The Jordan Valley has been a target for demolitions by Israel's Civil Administration, with several structures in villages across the area being torn down.
On Sunday, dozens of Palestinians as well as foreign activists rebuilt areas in the nearby Al-Farisiya village that were recently bulldozed by Israel's Civil Administration.
Over the past 10 days, several shacks, homes and agricultural structures were torn down in the village by the administration, which has complete planning and building control over Area C. Last Thursday, the Civil Administration returned to the valley to demolish 23 structures rebuilt by residents and farmers.
Meanwhile, in the nearby Bardala village, locals said the Civil Administration distributed several stop-work orders to residents in late July.
The orders, known locally as "demolition orders," demand that homeowners appear before a magistrates court to defend allegations. Because legal action at the court rarely succeeds, the stop-work orders essentially constitute a demolition order.
According to a report in the Israeli daily Haaretz in July, the Civil Administration has received government orders to increase enforcement against Palestinian construction in Area C, according to a deposition by an administration official to the High Court.
The deposition, by the head of the administration's infrastructure authority, Colonel Zvika Cohen, came in response to a petition by Regavim - a group seeking the destruction of illegal Palestinian construction at six West Bank sites, citing a security threat, the daily reported.
A recent UN report said 86 structures in the Jordan Valley were demolished two weeks ago, and 17 others were demolished in other areas of the West Bank the week after.
"The spate of demolitions raises concerns over whether Israeli authorities could further escalate demolitions throughout Area C," a UN report said, noting more than 3,000 demolition orders handed down by Israeli officials to locals were still outstanding.
"Currently, it is nearly impossible for Palestinians to obtain building permits to maintain, repair or construct homes, animal shelters or necessary infrastructure in Area C," the UN Office for the Coordination of Humanitarian Affairs said in its latest report on Area C.