U.S. Embassy in Ankara, Turkey hit by suicide blast; 1 dead, U.S. officials say Updated at 12:04 p.m. ANKARA, Turkey A suicide bomber detonated an explosive device at an entrance to the U.S. Embassy in the Turkish capital on Friday, killing himself and one other person, officials said. Deadly explosion at U.S. Embassy in Turkey 16 Photos Suicide bomber hits U.S. Embassy in Turkey U.S. Ambassador Francis Ricciardione told reporters that a guard at the gate was killed in the 1:15 p.m. blast, and a Turkish citizen was wounded. Reuters quoted Ricciardione as saying the slain guard was a Turkish national. The bomb appeared to have exploded inside the security checkpoint at the side entrance of the embassy, but did not do damage inside the embassy itself. Footage showed that the door had been blown off its hinges and debris littered the ground and across the road. An Associated Press journalist saw a body in the street in front of an embassy side entrance. Turkish Prime Minister Recep Tayyip Erdogan confirmed that it had been a suicide attack. White House spokesman Jay Carney called the attack "an act of terror." There was no immediate claim of responsibility, but Interior Minister Muammer Guler told reporters "preliminary information" obtained by police indicated that the bomber was likely connected to a domestic left-wing militant group. He did not elaborate. A police official, meanwhile, told The Associated Press that the bomber is most likely a suspected member of the outlawed Revolutionary People's Liberation Party-Front, or DHKP-C. He spoke on condition of anonymity because he was not permitted to speak to the press. The group has been designated a terrorist organization by the United States but had been relatively quiet in recent years. A source familiar with security at the embassy in Turkey told CBS News correspondent Margaret Brennan that, in their view, the security measures taken at the compound seemed to have worked, in that the attacker was unable to gain access to the main embassy building. The source said the U.S. Embassy in Ankara is considered a high-security post, and there are Turkish police present at all times. All gates leading into the compound are manned by armed Turkish security guards, according to the source. Police swarmed the area and several ambulances were dispatched. An AP journalist saw one woman who appeared to be seriously injured being carried into an ambulance. The embassy building is heavily protected. It is near an area where several other embassies are located, including that of Germany and France. Police sealed off the area and journalists were being kept away. Homegrown Islamic militants tied to al Qaeda have carried out suicide bombings in Istanbul, killing 58, in 2003. The targets were the British consulate, a British bank and two synagogues. In 2008, an attack blamed on al Qaeda-affiliated militants outside the U.S. Consulate in Istanbul left three assailants and three policemen dead. In the November 2003 attack on the British consulate, a suspected Islamic militant rammed an explosive-laden pickup truck into the main gate, killing British Consul-General, Roger Short, and his assistant, Lisa Hallworth. CBS News senior correspondent John Miller, a former deputy director in the National Intelligence Director's office, noted on "CBS This Morning" the possibility of a connection to the recent Israeli airstrike in Syria, for which Damascus and its staunch ally Iran vowed to retaliate. Iran, Miller says, has extensive intelligence operations in Turkey, and its Islamic militant group ally, Hezbollah, also has significant assets there. "Iran, in terms of retribution, would stack Israel and the U.S. together," says Miller. Turkey has become a harsh critic of the regime in Syria, where a vicious civil war has left at least 60,000 people dead. The first of six Patriot missile batteries being deployed to Turkey to protect against attack from Syria was declared operational and placed under NATO command on Saturday and others were expected to be operational in the coming days.