Suspected Israeli missiles targeted an Iran-linked army base south of Syria’s capital, Damascus, on Tuesday, shortly after President Donald Trump said the U.S. would withdraw from the international nuclear deal with Iran.

Syrian state and pro-regime media said the country’s air defenses had downed two Israeli missiles. Photos on social media appeared to show fires in al-Kiswah, an industrial area home to an army base, after it was hit. Opposition activists in Damascus said there was ambulance traffic from Damascus to the site...