Secret Chinese Port Project in Persian Gulf Rattles U.S. Relations With U.A.E.

WASHINGTON—U.S. intelligence agencies learned this spring that China was secretly building what they suspected was a military facility at a port in the United Arab Emirates, one of the U.S.’s closest Mideast allies, according to people familiar with the matter.

Alarmed, the Biden administration warned the Emirati government that a Chinese military presence in its country could threaten ties between the two nations. After rounds of meetings and visits by U.S. officials, construction was recently halted, according to people familiar with the matter.

The intelligence findings and U.S. warnings concerned...