Alexanda Kotey, left, and El Shafee Elsheikh, who were allegedly among four British militants who made up a brutal Islamic State cell dubbed "The Beatles," speak during an interview with the Associated Press at a security center in Kobani, Syria, on March 30, 2018. (Hussein Malla/AP)

Two admitted Islamic State militants are expected to be flown on Wednesday from Iraq to the United States, where they will become the first defendants to face prosecution in a U.S. court in connection with the beheadings of American and British hostages, U.S. officials said.

Charges against El Shafee Elsheikh and Alexanda Kotey are expected to be unveiled Wednesday in crimes related to the brutal executions of journalists and aid workers by the Islamic State in Syria, said the officials, who spoke on the condition of anonymity because of the matter’s sensitivity.

They will be prosecuted in federal court in Alexandria, Va., the site of many past high-profile ­national security cases. Officials would not detail the planned charges, but possible counts include conspiracy to commit homicide, hostage-taking resulting in death, kidnapping resulting in death and homicide.

The pair are being flown to the United States by the U.S. military, which has been holding them at an air base in Iraq since October 2019.

The mother of one of the men had sought to block a U.S. prosecution because of the prospect of the defendants facing execution if convicted. But a British court last month effectively ended her efforts, paving the way for the two militants, whom Britain earlier stripped of their citizenship, to be tried in the United States.

“We appreciate Britain’s providing the evidence in support of prosecution and we look forward to seeing these defendants in a U.S. courtroom to face justice in the near future,” Justice Department spokesman Marc Raimondi said. He declined to comment on the charges.

Attorney General William P. Barr in August agreed to set aside the possibility of a death sentence if British authorities promptly transferred evidence to aid a U.S. prosecution. That evidence was shared two weeks ago as soon as the British court issued its ruling.

The pair were part of a four-member cell dubbed “the Beatles” by their prisoners because of their British accents, and are accused of helping stage the beheadings, which were posted online, as the Islamic State was taking control of Iraq and Syria in 2014.

The most infamous of the four was the masked man who carried out the grisly killings, known as “Jihadi John,” and identified as Mohamed Emwazi not long before he was killed in 2015 in a U.S. drone strike. A fourth member of the cell is imprisoned in Turkey.

Elsheikh and Kotey were captured by Kurdish forces in Syria in 2018. They were transferred to Iraq by the U.S. military in October 2019 amid Turkey’s invasion of northeast Syria.

All four traveled to Islamic State territory from homes in London, and British authorities have amassed substantial evidence related to those journeys as well as voice analysis connecting the suspects to the hostages. But the British government was reluctant to try them in domestic court, fearing that even if the men were convicted, British law would not guarantee a sufficient sentence.

Barr had given British officials until Oct. 15 to provide the evidence or, he warned, the men would be transferred from U.S. custody to the Iraqi government for prosecution. Such a move, human rights activists said, would be tantamount to a death sentence.

Former hostages said the group subjected them to repeated beatings, waterboarding and mock executions.

A number of Western European hostages were released after their governments paid ransoms. The British and U.S. governments refused to do so. Emwazi beheaded American journalists James Foley and Steven Sotloff on camera, as well as British aid workers David Haines and Alan Henning. Peter Kassig, an American aid worker, was slain before his severed head was displayed in an ISIS video. Kayla Mueller, an American human rights activist, was also killed while being held by the group, but her body has not been found.

In interviews from Kurdish custody with The Washington Post and other news organizations, Kotey and Elsheikh acknowledged interacting with those hostages, saying it was their job to extract information, sometimes violently, that could be used in ransom negotiations. But they said they didn’t participate in the executions.

Missy Ryan contributed to this report.