Many prisons in Iraq are packed with IS suspects.

In February, the United States completed the transfer of 5,700 IS detainees, including hundreds of foreigners, from Syria to Iraq.

The National Centre for International Judicial Cooperation (NCIJC) said it has handed "two suspects -- a minor from Finland and another from the United States -- to the competent authorities in their countries after it was confirmed that they don't belong to the Daesh terrorists", using an Arabic acronym for IS.

"The handover took place after all legal and judicial procedures were completed," the judiciary said in a statement carried by the Iraqi News Agency (INA).

The judiciary did not specify whether the two detainees referred to were among those who had been transferred from Syria.

Upon the detainees' arrival in Iraq, the judiciary began interrogations before taking legal action against suspects from some 60 countries.

These include 3,543 Syrians, 467 Iraqis and 710 detainees from other Arab nations.

There are also more than 980 foreigners including from Europe, Asia, Australia and the United States.

IS swept across Syria and Iraq in 2014, committing massacres and forcing women and girls into sexual slavery.

Iraq, backed by US-led forces, proclaimed victory over IS in the country in 2017, and the Kurdish-led Syrian Democratic Forces ultimately defeated the group in Syria two years later.

Iraqi courts have handed down hundreds of death sentences and life terms to those convicted of terrorism offences, including foreign fighters.