International Criminal Court members will on Friday vote for the next prosecutor of a tribunal hit by controversy in recent months over investigations of American and Israeli suspects.
Envoys will vote in a secret poll to choose which of four candidates will replace Fatou Bensouda for a nine-year term when she steps down in June. The race has attracted unusually fierce competition.
Karim Khan, a British lawyer who heads a UN inquiry into ISIS crimes in Iraq, and Ireland's Fergal Gaynor, are tipped as frontrunners. Carlos Castresana of Spain and Francesco Lo Voi of Italy are also running.
Mr Khan has in recent days battled worries over UK policy to its colonial-era Chagos Islands and over whether he would drop cases into atrocities against Palestinians and by US forces in Afghanistan.
Georgetown Law professor Arjun Sethi on Twitter mentioned reservations about Mr Khan because he "may shut down" investigations into "US war crimes in Afghanistan and Israeli war crimes in Palestine".
The ICC last week ruled that it has jurisdiction over crimes committed on Palestinian land, a move that angered Israel. An inquiry into atrocities by Americans in Afghanistan led the Trump administration to sanction on Ms Bensouda and other court officials last year.
The court has mostly handled African cases.
A candidate must gain support from at least 62 of 123 voting ICC members, known as the Assembly of States Parties, to win. The process is the focus of lobbying by governments and campaigners and additional rounds of voting may be needed.
James Goldston, a legal scholar at the Open Society Foundations think tank, said the court had not properly vetted the candidates and that some were not right for the job.
"The election process should have been an important start to enhancing the court's credibility at such a critical point in its institutional development," Mr Goldston said.
“The ASP should urgently set up a permanent vetting mechanism for all future elections, including the election of future prosecutors and judges.”
Based in The Hague, in the Netherlands, the ICC was established in 1998 to prosecute people responsible for genocide, war crimes and crimes against humanity. It is currently pursuing more than a dozen cases across Africa, Asia and Europe.