The officials, speaking on condition of anonymity under army regulations, said the weapon uses special frequencies to disperse crowds. No further details were immediately available.

An Associated Press photographer said a military vehicle arrived toward the end of the demonstration, which lasted several hours and became violent at times.

Located about a quarter mile from the demonstration, the vehicle emitted several bursts of sounds, about one minute in length each time. Although the sound was not loud, it caused people to cover their ears and grab their heads in discomfort.

About 400 people, including Palestinians and foreign and Israeli activists, participated in the demonstration, marching toward a site where Israel is building its West Bank separation barrier.

The crowd was prevented from reaching the site, and began rioting and throwing rocks at soldiers, the army said. One soldier was moderately wounded in the eye.

In addition to the sound machine, soldiers used other means to disperse the crowd, including clubs and stun grenades.

Israel has completed about one-third of the planned 425-mile barrier, which it says is necessary to keep out suicide bombers from the West Bank. Palestinians say the barrier is a thinly veiled land grab because it dips into the West Bank in some areas.