Karim Khan (L), the lawyer for Abdallah Banda Abakaer Nourain (C) and Saleh Mohammed Jerbo Jamus (R), both suspected of having committed war crimes in Darfur, speaks at the International Criminal Court in The Hague June 17, 2010. REUTERS/Toussaint Kluiters/United Photos

British barrister Karim Khan took over as the International Criminal Court’s top prosecutor on Wednesday with a pledge to improve its track record by taking only its strongest cases to trial.

Khan, who is only the third person to hold the role, faces many challenges at a time of fierce political pressure on the world’s permanent war crimes tribunal.

The ICC is handling a number of sensitive cases, including in the Palestinian territories and Afghanistan, and members of the prosecutor’s office were personally targeted by financial sanctions while Donald Trump was US president.

Under Trump, Washington opposed decisions by Khan’s predecessor, Fatou Bensouda, to examine war crimes allegations in Afghanistan, including against US troops, and alleged atrocities in the Palestinian territories by Israeli troops, Palestinians and other armed groups.

The sanctions have been dropped, but US and Israeli opposition to the court remains.

Khan, 51, took an oath to serve his nine-year term honorably and impartially during a ceremony in The Hague. He said one of his main tasks would be improving the performance of the prosecutor’s office.

Since opening in 2002, the ICC has convicted five men for war crimes and crimes against humanity, all African militia leaders from Democratic Republic of Congo, Mali and Uganda. Sentences ranged from nine to 30 years in prison.

Prosecutors dropped or lost at least three major cases, or failed to gather enough evidence in others to proceed to trial.

“Opening preliminary examinations, requesting authorization or commencing investigations is a start, but as we say in English the proof of the pudding is in the eating. We have to perform in trial,” Khan said.

“We cannot invest so much, we cannot raise expectations so high and achieve so little, so often in the courtroom,” he said. “We need a greater realization of what is required … Building stronger cases and getting better cases in the courtroom.”

Already short of resources, the ICC is dealing with 14 full-blown investigations and eight preliminary examinations.

Khan also inherits investigations opened in countries including Myanmar, the Philippines and Ukraine.