The children around the world who need emergency international assistance the most come mainly from the countries singled out in President Trump’s order barring entry to the United States, according to a United Nations assessment.

Five of the seven countries where children are most imperiled are on Mr. Trump’s list of nations where visas are suspended: Iraq, Somalia, Sudan, Syria and Yemen.

The children most at risk are Syrian, whether they have fled as refugees or are still in their country, according to Unicef, the United Nations’ children’s agency. All Syrians have been barred indefinitely from entering the United States under Mr. Trump’s executive order.