No one was injured in the attack, local media report. The shooting took place at about 5am local time (2am GMT). Five or six gunshots were heard near the security guard's cabin at the embassy's Gate 6. They came from a white car that drove by and escaped before its license plate number could be determined.
Police have been dispatched to the scene and the search for the car and the fugitives is ongoing.
The attack comes at a time when relations between NATO allies US and Turkey are rapidly souring over the detention of American pastor Andrew Brunson in Turkey. Brunson is accused of aiding the 2016 coup attempt and faces up to 35 years in prison. The US Treasury has imposed sanctions on the Turkish ministers of justice and interior, and US President Donald Trump ramped up tariffs on aluminum and steel imports the country.
The economic pressure sent the Turkish national currency, the lira, plunging to unprecedented lows. Turkish President Recep Tayyip Erdogan has accused Washington of deliberate attacks on Ankara's economy and urged his people to drop the dollar in favor of the lira.
Comment: US-Turkish relations are heating up by the day.