Iran closed the airspace over the western part of the country to all flights until Monday, another sign that the United States may resume its air campaign against Iran.

The Civil Aviation Authority of the Islamic Republic of Iran issued the notice to airmen late on Friday, canceling all remaining flights until the next morning. The sudden move added to a growing cache of evidence suggesting a possible reignition of the war with Iran, which has been under a fragile ceasefire since early April.