Days after the Islamic State’s leader, Abu Bakr al-Baghdadi, and his heir apparent were killed in back-to-back attacks by United States forces in northern Syria, the group broke its silence on Thursday to confirm their deaths, announce a new leader and warn America: “Do not be happy.”
In an audio recording uploaded on the Telegram app, the Islamic State mourned the loss of Mr. al-Baghdadi, who led the organization for nearly a decade, and its spokesman, Abu Hassan al-Muhajir, who was killed a day after Mr. al-Baghdadi and who had widely been considered a potential successor.
The audio recording was the first word from the Islamic State confirming the death of its leader, which President Trump triumphantly announced on Sunday as a huge blow to the world’s most fearsome terrorist group.
Mr. Trump and Pentagon officials said Mr. al-Baghdadi had blown himself up with a suicide vest, also killing two children, after he had been cornered on Saturday in a dead-end tunnel during an American military raid in a northern Syrian village. Mr. al-Muhajir was killed on Sunday in an airstrike elsewhere in northern Syria.
Mr. al-Baghdadi’s death came eight months after American-led forces in Syria seized the last remnants of the territory once held by the Islamic State, which at its height spanned an area the size of Britain across parts of Syria and Iraq.
The Islamic State announcement said that Mr. al-Baghdadi had been succeeded as leader by Ibrahim al-Hashemi al-Qurayshi, whom it identified as the “emir of the believers” and “caliph.” Mr. al-Qurayshi appeared to be largely unknown, at least outside the ranks of the organization.
The al-Qurayshi appellation at the end of the new leader’s name indicates that he is being portrayed as a descendant of the Quraysh tribe of the Prophet Muhammad, a lineage that the Islamic State considers to be a prerequisite for becoming a caliph or ruler.
Its use indicates that the Islamic State, also known as ISIS, ISIL and Daesh, continues to see itself as a caliphate — even if one with practically no territory.
“It shows that while the world is ready to pronounce the Islamic State dead and finished, the group’s core leadership continues to believe it can operate much as it has in the past,” said Colin P. Clarke, a senior fellow at the Soufan Center, a research organization in New York.
“The suggestion is that nothing changes, allegiance should still be to the leadership, and affiliates and franchises should continue to look to al-Qurayshi for guidance on how to operate,” he said.
The announcement, in a seven-minute, 37-second recording, was coupled with a warning to the United States not to gloat over killing Mr. al-Baghdadi, who oversaw beheadings of American hostages and other atrocities.
“Do not be happy O America, for the death of Sheikh al-Baghdadi, and do not forget the cups of death at his hands, may God accept him,” the announcement said.
It boasted of the group’s disciples and expansion beyond the Middle East, even as its core territory in Iraq and Syria was reduced to nil: “Don’t you see America that the State is now on the threshold of Europe and Central Africa?”
The announcement also took aim at the leadership of Mr. Trump, admonishing the United States: “Don’t you see how you became the laughingstock of the nations, and an old and crazy man controls your fate, whose opinion changes between morning and evening?”
The announcement implied that the Islamic State hierarchy had convened in order to discuss the successor question and suggested that he had been handpicked in advance by Mr. al-Baghdadi: “The sheikhs of the mujahedeen agreed, after consulting with their brothers and acting upon the recommendation of Abu Bakr al-Baghdadi, to pledge allegiance to the sheikh and mujahid, the scholar, doer and worshiper Abu Ibrahim al-Hashemi al-Qurayshi,” the announcement said.
It also called upon supporters to pledge allegiance to the new leader, a ritual that took new meaning under Mr. al-Baghdadi’s reign, as attackers around the world recorded video pledges of fealty to the caliph before carrying out killings.
Intelligence officials and analysts were rushing to try to make sense of the announcement and to place the announced successor among the known cadre of the Islamic State. Some speculated that Abu Ibrahim al-Hashemi may be a new nom de guerre of Hajji Abdullah, who appears in recently recovered internal Islamic State records archived by Aymenn al-Tamimi, a researcher.
The recent announcement by the State Department of a $5 million reward for information leading to his capture was a sign of the importance that the United States placed on him.
Besides the new leader, the Islamic State announcement also proclaimed a new spokesman, identified as Abu Hamza al-Qurayshi, again using a name indicating a lineage from the Prophet’s tribe, and setting up another potential successor.
“Those names are the most generic names I can think of in a long time,” said Daniele Raineri, a journalist and analyst who has been studying the Islamic State’s leadership structure for more than a decade. “This trick is obfuscating on purpose the possible links to people we know.”
Eric Schmitt, Evan Hill and Rick Gladstone contributed reporting.