ZINTAN, Libya — Rebels in the mountains in Libya’s west have looted and damaged four towns seized since last month from the forces of Col. Muammar el-Qaddafi, part of a series of abuses and apparent reprisals against suspected loyalists that have chased residents of these towns away, Human Rights Watch said Tuesday.

The looting included many businesses and at least two medical centers that, like the towns, are now deserted and bare.

Rebel fighters also beat people suspected of being loyalists and burned their homes, the organization said.

The towns that have suffered the abuses are Qawalish, which rebels seized last week, Awaniya, Rayaniyah and Zawiyat al-Bagul, which fell to the rebels last month. Some of the abuses, Human Rights Watch said, were directed against members of the Mashaashia tribe, which has long supported Colonel Qaddafi.