Turkish broadcaster NTV said the explosion caused no damage inside the embassy while a video showed damage to a checkpoint.
Dozens of ambulances and fire engines rushed to the scene after the explosion. No group claimed responsibility for the attack.
The area is home to other diplomatic missions also.
A report said a member of the embassy's Turkish staff had been killed but could not be confirmed, BBC said.
Embassy staff were taken to secure rooms in the building, NTV said.
A witness who works in an office opposite the embassy told BBC he was certain it was a suicide bomber and that he saw a body being removed by ambulance.
While the blast was very loud, the damage seemed to have been limited to the vicinity of the blast and no smoke was visible afterwards.
The last major attack in Ankara was in 2007, when a lone suicide bomber killed nine people and injured 120.
A number of banned groups and Islamist militants have launched attacks in recent years in Turkey.