A Turkish security guard was killed and three people wounded in a suicide bombing at the United States embassy in Ankara on Friday.
The force of the blast damaged nearby buildings in the Cankaya neighbourhood of the capital where many state institutions and embassies are also located.
NTV television reported the bomber detonated the explosives at a security roadblock near the entrance to the embassy's visa section, where dozens of people wait every day.
The incident occurred at a side entrance to the embassy at 1.15pm. The explosion blew the door off the entrance checkpoint and sent debris flying into the street.
The US has warned its citizens not to visit diplomatic missions in Turkey until further notice.
No group has said it carried out the attack, but Interior Minister Muammer Guler said might have been a member of the Revolutionary People's Liberation Party-Front, an outlawed organisation.
Turkey and the United States have denounced the incident as terrorism.
Ankara was last hit by a suicide bombing in September 2011.