"If we consider that the occupation ends June 30, that would mean it's the end of the international armed conflict," Nada Doumani of the International Committee of the Red Cross told the news agency by phone from Baghdad.

According to article 118 of the third Geneva Convention, prisoners of war should be repatriated without delay at the end of hostilities. Article 133 of the fourth convention says that interned civilians should also be released when conflict ends.

It remains to be seen whether the occupation effectively ends with the handover of sovereignty, however, and Doumani stressed that "the situation on the ground determines the facts."

"This is the legal situation: When the conflict ends the prisoners of war should be released according to the Geneva Conventions," she explained. "Therefore ... all people detained in relation to the conflict should be released unless there are penal charges against them."

Although Iraqis will run their own affairs after June 30, about 150,000 U.S. and other coalition troops will remain in the country to help improve security under a U.N. resolution approved unanimously by the U.N. Security Council on Tuesday.

After the handover of sovereignty, detainees held by the Iraqi authorities will be subject to Iraqi law. But current prisoners who are not released because they face penal charges will remain under the protection of the Geneva Conventions, Doumani said.

In an interview published Saturday in the daily Neue Zuercher Zeiting, ICRC President Jakob Kellenberger said it was unclear which authorities the Red Cross should deal with after the transfer of sovereignty.

The ICRC is empowered under the 1949 Geneva Conventions to visit prisoners of war and other detainees and make sure their care meets international standards.

"In principle all prisoners of war and interned civilians must be released July 1," Kellenberger said. "If prisoners remain under the responsibility of the multinational troops, then we'll have to check whom we should report to. We will negotiate directly with the Iraqi authorities over our visits to prisoners in their care."