Washington: The US described as a "terrorist attack" the blast outside its highly-fortified Embassy in Turkey on Friday that claimed two lives and injured three others.
The White House strongly condemned the suicide attack, saying it was "clearly an act of terror", while outgoing Secretary of State Hillary Clinton Clinton spoke with her Turkish counterpart Ahmet Davutoglu on the incident.
"A suicide bombing on the perimeter of an embassy is by definition an act of terror. However, we do not know at this point who is responsible or the motivations behind the attack. The attack itself is clearly an act of terror," White House Press Secretary Jay Carney told reporters at his daily news conference.
"Clinton spoke with her Turkish counterpart on the terrorist attack," her spokesperson Victoria Nuland said at another news conference.
"She was briefed immediately after the incident and all through the morning. She determined very quickly that she wanted to speak to (US) Ambassador (to Turkey) Francis Ricciardone and the staff and then she wanted to talk to Foreign Minister Davutoglu.
In the conversation with Davutoglu, she obviously expressed condolences for the loss of life. He expressed grave concern for the fact that this had happened," Nuland said.
"She also thanked him for the absolutely excellent cooperation that we`ve had from Turkish law enforcement. Let me just underscore that point. Turkish national police, in particular, responded immediately and have been cooperating superbly with us," Nuland said.
"Both of them in that phone call committed to the strong and ongoing counterterrorism partnership that the US and Turkey have had," she added.
"This incident obviously underscores the requirement that we stay very closely lashed up on all of these kinds of issues, not just the investigation of this incident, but counterterrorism more broadly across the region," Nuland said.
Strongly condemning the suicide attack against US embassy in Ankara, Carney said details are still emerging about what exactly happened, who was responsible.
"It was clearly an act of terror, and it cost the life of at least one individual, a Turkish security guard," he said.
The US is working closely with Turkish authorities to investigate the incident and bring the perpetrators to justice.
"Now, our thoughts and prayers go out to the families of those killed and injured, and we greatly appreciate the support we have received from our Turkish friends in responding to this terrible tragedy," he said.
Turkey remains one of the strongest partners of the US in the region.
"We have worked shoulder-to-shoulder with the Turks to counter terror threats. This goes to your question, and this will only strengthen our resolve. The Turkish has been a very important ally broadly speaking and in the effort to counter terrorism," he said.
Giving details of the incident, Nuland said one direct hired local guard was killed in the attack.
"We had two other direct-hire guards who were shaken up. They were on the other side of some bulletproof gas. We had a Turkish visitor who is in serious condition.
But the only other casualties here were several US and Turkish staff who were struck by flying debris. They were treated on the site by our embassy clinic and released," she said.
"The level of security protection at our facility in Ankara ensured that there were not significantly more deaths and injuries than there could have been. We`re obviously working closely with Turkish authorities to make a full assessment of the damage and to begin to investigate this," she said.
Meanwhile, Turkish Prime Minister Recep Tayyip Erdogan blamed the Revolutionary People`s Liberation Front (DHKP-C), a radical leftwing group, for the attack. "It is definitely DHKP-C," Erdogan was quoted as saying by Turkish media.