ISTANBUL — A Marxist group with a history of political violence in Turkey claimed responsibility on Saturday for a suicide bombing at the American 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 American 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 Web site that has previously carried statements from the group, condemned Turkey for its cooperation with the United States and for its policy of supporting Syrian rebels fighting the government of President Bashar al-Assad.

After conducting DNA tests, the Turkish authorities on Saturday identified the man who detonated himself at the embassy, killing himself and a Turkish guard, as Ecevit Sanli, 40, also known as Alisan Sanli. Mr. 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 lived there.

The Ankara police said they had detained three people thought to have helped Mr. Sanli and had found a handgun linked to the militant group. They also released security footage from the embassy in which Mr. Sanli was shown pretending to be a courier.