The US-backed Iraqi government is being pressured to start an enquiry into the matter of the secret prison in Baghdad, where the inmates reported that they've been tortured.

"We insist on having an international investigation", Islamic Party spokesman Alaa Makki told AFP.

"There have been similar cases in the past and investigations into them led to nothing", said another party spokesman, Ayad Samarrai.

"We want an international and impartial inquiry as we are beginning to think there are people high up in government who are responsible, or at least accomplices."

According to Reuters, an Iraqi student said he was hung blindfolded in the most painful positions, while the Shiite interrogators called him a "Sunni dog".

The Iraqi PM Ibrahim al-Jaafari confirmed on Tuesday that 173 prisoners were found malnourished and possibly tortured.

"Such crimes are committed by parties who wish to curb the political process, to stop Sunnis from taking part in the coming elections within only one month, to hinder our election campaigns", Islamic Party official Tariq Al-Hashemi said.

The Iraqi officials announced on October 25 the results of the referendum in which the population expressed their vote regarding the adoption of a US backed constitution. Iraq's Electoral Commission revealed that, on October 15th, 79% voted in favor of the new constitution, while 21% voted against.

The constitution's final results confirmed that only two of Iraq's 18 provinces, the insurgent stronghold of Anbar in the west and Saddam Hussein's home region of Salahaddin, had mustered a "No" vote of at least two-thirds.

The Iraqis will have one more voting job to carry out, the parliamentary elections on December 15, an event which will surely lead to more bloodshed between the two groups.