Six shots were fired at the embassy early on Monday, with three bullets hitting the iron gate and window wall, the Ankara governor’s office said.
“There are no casualties,” it added.
The US embassy spokesman David Gainer confirmed to Agence France-Presse that a “security incident” had taken place.
“We have no reports of any injuries and we are investigating the details. We thank the Turkish national police for their rapid response,” he said.
A bullet mark was visible on a security booth at the embassy, an AFP journalist at the scene reported.
Ömer Çelik, a spokesman for the ruling Justice and Development Party (AKP), called the incident an “open provocation”, but did not elaborate.
Ankara and Washington are locked in a dispute over Turkey’s detention of an American pastor on terror-related charges.
Also, President Donald Trump has doubled the tariffs on aluminium and steel imports from Turkey, prompting Ankara to sharply hike tariffs on several US products.
Last week, Turkey threatened to respond in kind if Washington imposed further sanctions, while a court rejected another appeal to free the pastor Andrew Brunson.
The diplomatic standoff has sent the Turkish currency into freefall against the dollar, with President Recep Tayyip Erdoğan vowing to emerge victorious from the crisis.
In a written statement before the Muslim feast of Eid al-Adha, Erdoğan said: “The attack aimed at our economy has no difference from an attack aimed at our call to prayer or flag.”
The president said those who believed they would bring Turkey to its knees through the foreign currency exchange rate would “soon see they are mistaken”.