DUBAI, United Arab Emirates — The top US Air Force general in the Middle East warned on Thursday that Iran-backed militias could resume attacks in the region against the United States and its allies as tensions rise — assaults that could lead to a new Mideast escalation.

Speaking to journalists before stepping into his new role at al-Udeid Air Base in Qatar, with responsibility for military operations in Iraq, Syria, Afghanistan, and across the region, Lt. Gen. Alexus Grynkewich also expressed fears over Russian and Chinese influence taking hold as superpowers vie for economic and military influence in the Middle East.

Iran’s mission to the United Nations did not immediately respond to a request for comment.