GENEVA -- European Union candidate Renato Ruggiero of Italy, assured of U.S. approval, looked set Tuesday to become first long-term head of the new World Trade Organization.


Diplomats said the U.S. swing behind Ruggiero and the withdrawal of his only remaining rival Kim Chul-su of South Korea left little doubt that he would be appointed WTO director-general, perhaps later this week.


But they cautioned that some countries in the WTO could withhold immediate approval to signal displeasure that the key decision had been made in a deal between the big trade powers.


News of the shift by the United States, which had earlier hinted it might block Ruggiero, and of South Korea's move to pull Kim out of the nine-month contest came initially in overnight official leaks in Washington and Seoul.


In Geneva, WTO General Council chairman Krishnasamy Kesavapany of Singapore said he had been officially notified of the twin developments early in the day.


Formal confirmation from Washington was expected later Tuesday when Trade Representative Mickey Kantor, who had earlier been reported opposed to the Italian, appears with Ruggiero.


Kesavapany, who has been conducting consultations among the 127 present and pending members of the WTO said he would be reporting to envoys later in the day.


The WTO, launched Jan. 1 to absorb the old General Agreement on Tariffs and Trade, will administer new and tougher rules aimed at removing barriers to world trade. Former GATT chief Peter Sutherland has been heading the WTO on an interim basis.


Ruggiero is currently roving ambassador for Fiat motor group after three decades in government, diplomacy and business.


Seoul's state radio said Kim had agreed to withdraw under a deal in which he would be appointed as deputy to Ruggiero. U.S. newspapers said the EU had also agreed that the Italian would only hold the post for four years.


Geneva diplomats said there was little doubt Kim, also a former trade minister who had the backing of Asia-Pacific countries, would become the fourth deputy Director-General alongside the three currently in place.


But in Brussels an EU spokesman denied any terms had been negotiated with the United States in return for its clearly reluctant backing of Ruggiero.