By Gabrielle Tétrault-Farber and Emma Farge
GENEVA (Reuters) - European countries and the United States are running rival candidates to head the U.N. migration agency in an unusually tense contest between allies that opens in Geneva on Monday.
More than 100 million people are forcibly displaced around the world and the International Organization for Migration's (IOM) seeks to ensure humane and orderly migration, intervening in emergencies to help the vulnerable.
Its 175 member states will vote by secret ballot in closed-door meetings starting on Monday morning.
The candidates are IOM deputy director Amy Pope, a former White House advisor personally backed by U.S. President Joe Biden, and her boss António Vitorino from Portugal who has run the organisation since 2018.
Pope announced her campaign last year and took unpaid leave from IOM to focus on it from March, tweeting pictures of herself meeting officials all over the world. She pledges to "proactively address the challenges of migration and harness its benefits" and says she will focus on its root causes.
Vitorino, a former European Commissioner who is close to United Nations Secretary General Antonio Guterres, has touted an increase in the body's annual budget among his successes.
Asked about the contest, he admitted it was unprecedented.
"We have never happened to have an incumbent director general that faces a competition with one of his deputy generals. Let's call it an innovation," he told journalists. He said he had Portugal's backing as well as the "strong encouragement" of the European Union.
Diplomats said there had been strong pressure from both candidates in recent weeks and expect multiple rounds of votes in order for one candidate to score the two-thirds majority required by the IOM constitution. Both have privately told them they are confident of success.
One diplomat jokingly expressed relief that the ballot would be secret, to avoid drawing the wrath of either Brussels or Washington.
Voting could run into Tuesday, depending on the number of rounds.
(Reporting by Emma Farge and Gabrielle Tetrault-Farber; Editing by Alex Richardson)