Opponents of the US military presence in Japan's Okinawa prefecture want the troops moved out of the area. (EPA Images pic)

TOKYO: US soldiers stationed on Japan's Okinawa have been given a month-long curfew and banned from drinking alcohol while they undergo discipline training after a Marine was alleged to have murdered and robbed a local woman.

Lance Corporal Devin Jacob Ballard, 20, is suspected of killing Anna Yagi, 39, in a hotel in Naha, the capital of the southernmost prefecture, on Saturday and taking her wallet and backpack. "Ballard denied the allegations," police said.

The case is the latest in a string of incidents stretching back years that have fuelled unease over the large US troop presence on the island chain near Taiwan and China, with US officials warning it could undermine ties vital to security in East Asia.