The Israeli military says an American man has been critically wounded in a clash between protesters and Israeli troops over Israel's West Bank separation barrier.

Protesters said one of their colleagues, Tristan Anderson from the Oakland, California-area, was hit in the head with a tear gas canister Friday.

The military had no details on how the injury occurred.

The protest took place in the Palestinian town of Naalin, the scene of frequent clashes against Israel's West Bank separation barrier. The barrier runs through farmland belonging to the town.

The military says the area is a closed military zone and has banned demonstrations.

It said demonstrators hurled rocks at troops, who used riot gear to quell the unrest.