ISTANBUL — A Marxist group with a history of political violence in Turkey claimed responsibility on Saturday for a suicide bombing at the US Embassy in Ankara the day before, releasing a statement calling the United States ‘‘the murderer of the peoples of the world.’’
The statement, which also denounced US foreign policy, was released by the Revolutionary People’s Liberation Party-Front, and a translation was distributed by the SITE Intelligence Group, which monitors the communications of extremist groups.
The message, which was posted on a website that has in the past had statements from the group, condemned Turkey’s policy of supporting Syrian rebels fighting the government of President Bashar Assad and cooperation with the United States.
After conducting DNA tests, Turkish authorities Saturday identified the man who detonated explosives at the embassy, killing himself and a Turkish embassy guard, as Ecevit Sanli, 40, also known as Alisan Sanli.
Sanli was a convicted terrorist who had twice attacked government facilities in Istanbul but was released from prison under an amnesty program. Earlier Saturday, officials in the Black Sea town of Ordu said he was a resident.
The Ankara police said they had detained three people thought to have helped Sanli and had found a handgun linked to the militant group. They also released security footage from the embassy in which Sanli was shown pretending to be a courier.
The statement by the group included two photographs of Sanli. In one, he is holding an assault rifle, and a banner bearing the hammer-and-sickle symbol of communism is behind him.
The attack, coming in the wake of the attack on a US diplomatic mission in Benghazi, Libya, by Islamic extremists in September, initially raised fears that it was the work of jihadists. That the bomber has ties to a relatively minor Marxist group is likely to challenge assumptions about the nature of international terrorism and the risks to US interests abroad.
US officials have not confirmed the identity of the attacker or a motive. The United States plans to investigate.
In a statement on Saturday, Ordu officials said Sanli spent four years in prison after being arrested in 1997 for attacking a military hostel and police station in Istanbul.
He was freed in 2001 under an amnesty program for inmates with medical conditions, Muammer Guler, the interior minister, said. Sanli reportedly had Wernicke-Korsakoff syndrome, a brain disorder caused by malnutrition that he acquired during a jailhouse hunger strike.
The authorities said Sanli lobbed a hand grenade during Friday’s attack just before detonating his explosives-packed vest, suggesting that there were two explosions.
The Turkish newspaper Hurriyet reported that Sanli had fled to Germany after being released from prison, and according to the semiofficial Anatolian News Agency, he returned to Turkey illegally only a few days before the attack by taking a boat from a Greek island across the Aegean.
The group has struck American and other Western targets in Turkey before, including during the gulf war in the early 1990s, and in its statement the group condemned NATO’s recent deployment of Patriot missile batteries in southern Turkey to protect against cross-border strikes from Syria.
In a report published several days before the bombing, Soner Cagaptay, director of the Turkish research program at the Washington Institute for Near East Policy, warned that the country’s support of Syrian rebels was rallying Turkey’s extreme left.
“The country’s political landscape still bears vestiges of violent leftist movements from the 1970s, as well as deeply anti-American ultranationalism,’’ he wrote.
In the weeks before the attack, Turkish security forces arrested dozens of people thought to be members of the group, though human rights activists say those arrested have no links to terrorism.