WASHINGTON—The Trump administration is weighing an appeal from the United Arab Emirates for direct U.S. support to seize Yemen’s main port for humanitarian aid from Iranian-backed Houthi fighters, according to U.S. officials, a move they worry could have catastrophic effects on the country.

Secretary of State Mike Pompeo has asked for a quick assessment of the UAE’s plea for assistance such as surveillance drone flights to help a Saudi-led coalition retake Hodeidah, which currently serves as a vital lifeline for the country’s...