WASHINGTON -- One of the five accused Sept. 11 co-conspirators is asking a federal court to place a freeze on his ongoing military trial until the U.S. provides him with improved medical care at the Guantanamo Bay prison facility, where he has been detained since 2006.

Mustafa al-Hawsawi, who was held in CIA black sites from 2003 to 2006, has several chronic health problems that his lawyers say are the direct result of three years of abuse under the agencys torture program and inadequate medical treatment since being transferred to Guantanamo Bay.

On Thursday, his legal team will appear in federal court in Washington to urge the judge to halt proceedings at Guantanamo Bay, where al-Hawsawi is facing the death penalty for his alleged involvement in the Sept. 11, 2001 attacks.

The 46-year-old Saudi national was diagnosed with hepatitis C when he first arrived at the prison in September 2006 -- a condition his lawyers say he did not have before entering the CIA torture program. Since last year, there have been traces of blood in his urine and low red, white and platelet cell counts in his blood -- all possible signs of cancer. But al-Hawsawis lawyers say he hasnt received any medical tests to know for sure.

The Pentagon would not confirm whether al-Hawsawi had received tests to rule out cancer. "We do not discuss the individual medical records of detainees. With regards to public health screening of detainees, we follow and are in line with CDC and Bureau of Prisons (BOP) guidelines for medical care at detention facilities. Medical screenings are voluntary, said a spokesman for U.S. Southern Command.

Earlier this year, Abu Anas al-Libi, another U.S. prisoner with hepatitis C, died of complications related to the curable virus while in custody in federal prison in New York. Al-Libi, accused of helping to plan the 1998 U.S. embassy bombings in Kenya and Tanzania, died days before he was scheduled to appear in court. Mr. al-Libis case demonstrates the potential for sudden and deadly progression of hepatitis C, al-Hawsawis defense team wrote in a February court document.

CIA records show that al-Hawsawi also suffers from chronic hemorrhoids, an anal fissure, and symptomatic rectal prolapse. His lawyers say this is the direct result of sodomy with a foreign object under the guise of rectal exams conducted with excessive force, as described in a 528-page Senate report on the CIAs rendition, detention and interrogation program.

Al-Hawsawi now has to use his fingers to manually reinsert prolapsed tissue into his rectal cavity after straining or defecating, his legal team says. When al-Hawsawi appears in court, he has to sit atop a pillow.