CAIRO — The top United Nations court intervened Monday in the bitter political feud dividing the Persian Gulf, ordering the United Arab Emirates to allow the return of Qatari citizens expelled from the country last year.

The provisional order by the International Court of Justice, which is based in The Hague, is expected to have limited concrete effect. The court has no powers of enforcement and the United Arab Emirates, in response to the verdict, insisted it was already in compliance with it.

But the decision, by the most prominent international body to rule on the dispute, struck a symbolic blow to the punishing trade and diplomatic embargo that the United Arab Emirates and its allies — Saudi Arabia, Egypt and Bahrain — have been pressing against Qatar for the past year in an effort to isolate the tiny and fabulously wealthy nation.

“This sends an early, strong signal that there will be no tolerance shown to countries that take arbitrary measures against Qataris,” Lulwa al-Khater, a spokeswoman for Qatar’s foreign ministry, said in comments published by Qatar’s state media.