She said the commandos accused her of cooking for Sunni fighters and took her to a police camp where the attack occurred.
"One of them put his hand on my mouth so no one outside the room could hear me," she said in an AP videotape.
"I told them 'I did not know that an Iraqi could do this to another Iraqi'."
On Tuesday, Omar al-Juburi, the Iraqi vice-president's adviser on human-rights affairs, said that the prime minister's office should not have "rushed to issue such a confusing and uninformative statement" clearing the officers of the rape.
"This committee will have the last say on the incident ... Everybody knows that Ibn Sina is an unbiased hospital that cannot be affected by any sides"
Omar al-Juburi, the Iraqi vice-president's adviser on human rights affairs
Offices of the Iraqi vice-president and the interior minister have formed a new committee to investigate the incident, al-Juburi said.
He said: "The committee has a medical report from Ibn Sina hospital, where the raped woman was treated according to orders of the Iraqi vice-president.
"This committee will have the last say on the incident ... Everybody knows that Ibn Sina is an unbiased hospital that cannot be affected by any sides."
"We do not want to say anything about this issue before the committee completes the investigation and releases a statement on it," he added.
Al Jazeera, meanwhile, phoned the family of the woman and her husband said no investigation committee had contacted them so far.
The allegations are potentially explosive at a time of rising tensions between Shias and Sunnis as the US begins a security operation to restore order in the capital.
The victim did not specify that her attackers were Shias, although they form the majority within the ranks of Baghdad police, especially elite commando units.
On Monday, Hussein Ali Kamal, Iraq's deputy interior minister, disputed the rape allegation, saying "something like this could not happen because Iraqi forces are operating with US forces at all times".
On the other hand, Mahmoud al-Mashhadani, a top Sunni official and parliament speaker, said on Al-Jazeera, referring to al-Maliki: "By God, if you don't bring justice to this Muslim Iraqi woman, whom you should view as your sister or daughter ... history will curse us with eternal disgrace."
Rape victims rarely come forward because they fear public scorn and humiliation.
A woman who acknowledges being raped risks death at the hands of male relatives seeking to restore their family's honour.