The suicide bomber who detonated an explosive in front of the U.S. Embassy in Ankara is most likely connected to a domestic left-wing militant organization, Turkey's Interior Minister Muammer Guler has said.

A police official said that the bomber, who killed himself and a security guard, is most likely a suspected member of the outlawed Revolutionary People's Liberation Party Front. He spoke on condition of anonymity because he was not permitted to speak to the press.

A Turkish woman was also seriously wounded and two other guards sustained lighter wounds, Guler said.

The bomb 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.

Embassy heavily protected

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U.S. Ambassador to Turkey Francis Ricciardone, left, speaks with the media at the embassy. Canadian, British and Turkish officials all condemned the attack. (Reuters)

Turkish Prime Minister Recep Tayyip Erdogan said the attack demonstrated a need for international co-operation against terrorism and was aimed at disturbing Turkey's "peace and prosperity."

"But we will stand firm and we will overcome this together," he said.

In a statement, the U.S. Embassy thanked Turkey for "its solidarity and outrage over the incident."

The embassy building is heavily protected. It is near an area where several other embassies, including that of Germany and France, are located. Hurriyet newspaper said staff at the embassy took shelter in "safe room" inside the compound soon after the explosion.

Guler identified the injured woman as 38-year-old Didem Tuncay, a television journalist and a hospital official said she was "not in a critical condition." News reports said she was at the embassy to get a U.S. visa.

Previous attacks

Canadian Foreign Affairs Minister John Baird released a statement Friday condemning the attack, calling it a "cowardly act of violence."

All Canadians working at the Ankara embassy are safe, the government said.

Britain's Foreign Secretary William Hague condemned Friday's attack "in the strongest terms," and said Turkey and the U.S. will get the U.K.'s full support as they seek to hold those responsible to account.

Turkish Foreign Minister Ahmet Davutoglu, speaking to reporters during a visit to Belgrade, Serbia, said he was saddened that the attacked had occurred in Turkey.

"We have always shown great sensitivity to the protection of foreign missions and we will continue to do so," he said.

There was no claim of responsibility, but Kurdish rebels and Islamist militants are active in Turkey. Kurdish rebels, who are fighting for autonomy in the Kurdish-dominated southeast, have stepped up attacks in Turkey over the last year.

As well, homegrown 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.

Turkey has become a harsh critic of the regime in Syria, where a 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.