The U.S. Southern Command has been told to investigate alleged abuse by guards at Guantanamo Bay, Cuba, stemming from an Oct. 6 complaint by a Marine officer, the Pentagon's Inspector General's office said Friday.

Marine Lt. Col. Colby Vokey, who represents a detainee at the Guantanamo Bay prison, filed the "hot line" complaint to the Inspector General's office on Oct. 6.

In it, he attached a sworn statement from a Marine sergeant who works for him. The sergeant reported she listened as guards at Guantanamo Bay bragged about beating detainees and described it as a common practice.

The Marine, a paralegal who was at the U.S. Navy station in Cuba last month, alleges that several guards she talked to at the base club said they routinely hit detainees.

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"From the whole conversation, I understood that striking detainees was a common practice," the sergeant wrote. "Everyone in the group laughed at the others' stories of beating detainees."

Gary Comerford, spokesman for the Inspector General's office, told The Associated Press that in the past two days, the case "has been referred to Southcom for action. They're going to have to look into this."

The Miami-based Southern Command oversees military activities in the Caribbean and Latin America, and is responsible for the Guantanamo Bay detention center. Military spokesmen at Southern Command headquarters and at Guantanamo Bay had no immediate comment on the status of the investigation.

There are now 454 detainees at Guantanamo Bay, Vincent Lusser, a spokesman of the International Committee of the Red Cross, said Friday in Geneva. The Red Cross just completed a more than two-week visit to Guantanamo Bay, in which they met with 14 new detainees, including the alleged mastermind of the Sept. 11, 2001, attacks, who were transferred there weeks ago from CIA custody.

Guantanamo Bay began receiving prisoners, most of them captured in Afghanistan and Pakistan, in January 2002. Only 10 of the detainees have been charged with crimes.