"The Iraqi judiciary will begin standard legal proceedings against the defendants who are received and placed in the relevant correctional institutions," the Supreme Judicial Council said.

The US military said Wednesday it had launched an operation to move 7,000 IS prisoners from Syria to Iraq, as Syrian government forces moved on facilities long secured by Kurdish-led forces in Syria.

"All suspects, regardless of their nationalities or ranks within the terrorist organisation, are subject exclusively to the authority of the Iraqi judiciary, and our judicial procedures will be applied to them all without exception," the judiciary said.

Across the border in Syria, government forces have taken control of swathes of formerly Kurdish-held territory in the north and east.

That has included a deal struck over the weekend between the two sides that will see the Kurds' administration integrated into the state, while the government will take responsibility for IS prisoners.

Of the 7,000 IS detainees the US military aims to transfer from Syria to Iraq, the Iraqi government has so far confirmed the arrival of 150.

Thousands of suspected jihadists and their families, including foreigners, have been held in detention centres and camps in Syria since IS's defeat in 2019 at the hands of Kurdish-led forces backed by a US-led coalition.

- Death sentences, life behind bars -

At the height of its power, IS held swathes of Syria and Iraq, subjecting populations on both sides of the border to a horrific regime characterised by mass death, sexual slavery of women and girls, and punishment for anyone who dared voice dissent.

Iraqi courts have handed down hundreds of death sentences and life prison terms to people convicted of terrorism offences, including hundreds of foreign fighters -- some caught in Syria and transferred across the border.

In 2019, the courts sentenced 11 French nationals to death. Their sentences were later commuted to life in prison, according to a judicial source.

In September, Iraqi intelligence services were questioning 47 French nationals transferred from Syrian Kurdish custody over their alleged involvement in IS crimes committed in Iraq.

Some human rights groups have denounced "terrorism" trials in Iraq as rushed.

The country still has mass graves and many personal testimonies of IS brutality to be investigated.

In 2024, after a mission of the UN body investigating IS crimes ended, Iraq created the National Centre for International Judicial Cooperation to gather evidence and document IS crimes.

The centre serves as the main point of contact for foreign jurisdictions investigating alleged offences.