WASHINGTON, July 15 (Xinhuanet) -- The original 36-nation coalition led by the United States in the Iraq war has shrunk to 32 members and will shrink further soon, the Washington Post reported on Thursday.

    Four nations -- Spain, the Dominican Republic, Nicaragua and Honduras -- have left the coalition while Thailand, Norway, New Zealand and the Philippines are getting ready to leave the international force.

    US President George W. Bush and his administration is facing "growing challenges" to sustain the Iraq coalition, the newspapers said.

    The latest troop withdrawal wave came when the Philippine government offered to withdraw its 50-strong contingent in Iraq "as soon as possible" after a militant group threatened to kill a Filipino hostage unless Manila withdraws its contingent ahead of schedule.

    Manila planned to pull out its soldiers from Iraq before August20.

    In contrast to the Philippines, Norway quietly pulled out its 155 military engineers this month, leaving behind only about 15 personnel to train Iraqi security forces.

    New Zealand also intends to withdraw its 60 engineers by September and Thailand plans to pull out its more than 450 troops that same month, the newspaper said.

    In addition to the 140,000-strong US force, nearly 22,000 soldiers from the other coalition nations are deployed in Iraq. Enditem