Riot police stand guard during a protest outside the Iraqi capital Baghdad's Green Zone on Saturday, demanding the departure of remaining US forces from Iraq. Photo: AFP

The International Criminal Court's (ICC) chief prosecutor announced Wednesday she was shutting down a preliminary probe into alleged war crimes committed by British soldiers after the US-led invasion in Iraq.

Fatou Bensouda's announcement comes after a "rigorous" six-year long investigation into the conduct of British military personnel, particularly into the treatment of Iraqi prisoners in detention.

The prosecutor based in The Hague said in 2017 there was "reasonable basis" to believe British soldiers did commit war crimes. 

On Wednesday however, Bensouda said that she could not find any evidence that Britain had shielded suspects from prosecution before British courts.

"Having exhausted reasonable lines of enquiry arising from the information available, I therefore determined that the only professionally appropriate decision at this stage is to close the preliminary examination," Bensouda said in a statement.

As a result, the court will not proceed to a full ICC investigation.

Set up in 2002 as the only independent court to prosecute the world's worst crimes, the ICC is a "court of last resort," getting involved only if its member countries are unwilling or unable to prosecute suspects.

In June, an independent British investigator looking into allegations that UK soldiers committed war crimes in Iraq between 2003 and 2009 said that all but one of the thousands of complaints had been dropped.

AFP