The United States said Sunday that it would withdraw two Patriot missile-defense batteries from southern Turkey this fall, a sign that the Pentagon believes the risk of Syrian Army missile attacks has eased since the Patriots were deployed in 2013. Officials said the antimissile systems would be needed elsewhere to defend against threats from Iran and North Korea.

A statement issued by the United States Embassy in Ankara from the American and Turkish governments said the Patriots would be sent back to the United States for “critical modernization upgrades.” If needed in a crisis, the batteries and their 250 troops could be rushed back to Turkey “within one week” to fulfill an American and NATO commitment to Turkey’s air defenses. Air defenses aboard American warships in the region also could help carry out the security mission over Turkey, the statement said.