WASHINGTON (Reuters) - The U.S. Federal Aviation Administration is allowing U.S. airlines to resume operations over large areas of the Gulf, saying that a lower military posture by Iran has reduced the threat of miscalculation or misidentification of civilian flights.

A notice issued on Friday by the FAA rescinded restrictions imposed on U.S. air carriers in early January that prohibited flights over large swaths of the Gulf and the Gulf of Oman as tensions rose between Iran and the United States.

“Iran has de-escalated its military posture in the Persian Gulf and the Gulf of Oman as of early February 2020,” said the notice. “Given the de-escalation, the FAA assesses there is sufficient reduced risk of Iranian military miscalculation or misidentification that could affect U.S. civil aviation operations.”

The notice applied to the airspaces of Kuwait, Saudi Arabia, Bahrain, the United Arab Emirates and Oman.

The FAA, however, advised U.S. carriers to “exercise caution and avoid operating” near the boundaries of the Tehran flight information region “whenever possible.”

“Military posturing and political tensions in the region remain elevated, and there remains some inadvertent risk to U.S. civil aviation operations due to the potential for miscalculation or misidentification,” it said. “The situation in the region remains fluid and could quickly escalate if circumstances change.”

It cited the Jan. 8 accidental downing by Iran of a Ukrainian passenger jet shortly after it departed Tehran’s international airport, killing all 176 people aboard, as showing the inadvertent risk to civilian flights during periods of heightened military tensions.

Iranian forces downed the plane hours after firing missiles at bases in Iraq hosting U.S. troops. They were retaliating for a Jan. 2 U.S. drone strike that killed General Qassem Soleimani, the head of the Quds Force, Iran’s elite foreign espionage and paramilitary contingent, and the architect of Tehran’s regional security strategy.

In 1988, a U.S. Navy ship accidentally shot down an Iranian airliner over the Strait of Hormuz, killing all 290 passengers and crew.