Feb 1, 2013 11:33 AM by CNN
Tension is high in Turkey as questions loom Friday over who is responsible for a suicide bombing at the U.S. Embassy in Ankara.
A Turkish security guard was killed and the bomber died, authorities say.
There are conflicting accounts concerning how many were wounded.
Ankara police and health officials said two were injured while Ankara Gov. Aladdin Yuksel said one person was hurt.
A senior U.S. official said no Americans were wounded.
The "terrorist blast" occurred at 1:13 p.m. at a checkpoint on the perimeter of the embassy, U.S. State Department spokeswoman Victoria Nuland said.
"We are working closely with the Turkish national police to make a full assessment of the damage and the casualties, and to begin an investigation," she said.
Images from CNN sister network CNN Turk showed a hole in what appeared to be a building that is part of the outer gate of the embassy compound, which is in very well-protected area of Ankara near the Turkish parliament building.
The gated complex includes blast doors, reinforced windows and a series of metal detectors that visitors must navigate before reaching embassy offices.
The blast happened on the same day that Secretary of State Hillary Clinton is leaving her job. Sen. John Kerry will fill that role amid widespread discussion at the department over security at its global posts following last year's attack on the U.S. post in Benghazi, Libya.
Republican Rep. Ed Royce, chairman of the House Foreign Affairs Committee, issued a statement saying that the bombing Friday is "yet another stark reminder of the constant terrorist threat against U.S. facilities, personnel and interests abroad."
"Coming after Benghazi, it underscores the need for a comprehensive review of security at our diplomatic posts," his statement said. "The committee stands ready to assist the State Department in protecting our diplomats."
Vice President Joe Biden, in Europe to discuss issues such as the Syria conflict, spoke to reporters along with German Chancellor Angela Merkel, who said she is "very sad that there was an assault on the U.S. Embassy in Ankara. ... I want to send my condolences to everyone involved."
French Foreign Minister Laurent Fabius also condemned the attack and sent condolences.
Biden said he appreciated the sympathy. "I don't have much details to tell but it was characterized by our mission as a terrorist attack on our embassy in Ankara," he said. "To the best of our knowledge there were some injured. ... We don't have the details yet."
Turkish Prime Minster Recep Tayyip Erdogan said the blast was an attack "against the peace and welfare of our country."
Turkey has seen numerous acts of political violence in the past from groups such as leftist anarchists, Kurdish separatists, Islamists and al Qaeda. Turkey has also backed rebels in neighboring Syria, and some violence from that conflict has spilled over the border.
The explosion occurred as about 400 U.S. military personnel are moving Patriot missile defense batteries to Turkish locations as part of an effort to defend the country from possible attack from Syria. The first battery became operation last Saturday in the city of Adana, NATO said, and more arrived Wednesday in the port city of Iskenderun.
The British Embassy in Ankara strongly urged citizens to avoid areas around the U.S. Embassy.
The U.S. Embassy posted a message on its website thanking "the Turkish government, the media, and members of the public for their expressions of solidarity and outrage over the incident."
While the U.S. Embassy in Ankara has not seen this kind of incident in decades, in 2008 three police officers died in a shootout with assailants outside the U.S. Consulate in Istanbul.
Three attackers also died in the incident, which the U.S. ambassador at the time called "an obvious act of terrorism."
One of the attackers in that incident was believed to have trained with al Qaeda in Pakistan's Waziristan region.
CNN's Tim Lister, Barbara Starr, Elise Labott and Gul Tuysuz contributed to this report.
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