The United States will neither confirm nor deny that its ally Israel struck Syrian government facilities outside Damascus over the weekend.
State Department spokeswoman Jen Psaki said she had "seen the reports" but declined to comment on the development.
Syrian officials accused Israel of striking several targets in the town of Dimas and near Damascus International Airport. Israeli analysts and local media reports have suggested the targets were Iranian-made weapons bound for Lebanon.
Iran condemned the attacks on Monday, linking Israel's military "aggression" with that of Islamist extremists on the ground in Syria. Russia has also demanded an explanation from Israel of the attack.