The United States told the U.N. Security Council that the suspected ringleader of a deadly 2012 attack on its diplomatic compound in Benghazi planned to target more Americans and that justified his capture.
In a letter obtained by Reuters on Wednesday, U.S. Ambassador to the United Nations, Samantha Power, notified the council of the capture on Sunday of Ahmed Abu Khatallah by U.S. special forces in Libya after an investigation identified him as a key figure in the 2012 attack that killed four Americans.
"The investigation also determined that he continued to plan further armed attacks against U.S. persons," Power wrote in the letter dated Tuesday.
"The measures we have taken to capture Abu Khatallah in Libya were therefore necessary to prevent such armed attacks, and were taken in accordance with the United States' inherent right of self-defense," she wrote.
Power said the United States was reporting the capture of Khatallah to the Security Council under Article 51 of the U.N. Charter, which requires that the body be notified immediately of measures taken by states in self-defense against armed attack.
The brief letter also said Khatallah would be presented to U.S. Federal Court for criminal prosecution.
The attack on the U.S. compound killed four Americans, including the U.S. ambassador, and ignited a political firestorm in Washington.
President Barack Obama said in a statement he had authorized the operation in Libya on Sunday in which special forces, along with law enforcement personnel, captured Ahmed Abu Khatallah on the outskirts of Benghazi.
Special forces had shown "incredible courage" in the operation that captured Khatallah, he added.
The United States notified the Libyan government about the operation to capture Khatallah, the Pentagon said on Tuesday, but declined to say whether Libya was notified prior to the capture. A U.S. official, speaking on condition of anonymity, said Libya was not notified before the raid.
Obama says that Khatallah is being transported to the United States aboard a ship. He could face the death penalty if convicted.
"He is now being transported back to the United States. I say that first of all because we continue to think about and pray for the families of those who were killed during that terrible attack," Obama said during an event in Pennsylvania.
"But more importantly ... for us to send a message to the world that when Americans are attacked, no matter how long it takes, we will find those responsible and we will bring them to justice."
Khatallah was being held aboard the USS New York, an amphibious transport dock, a U.S. official said, speaking on condition of anonymity.
Rear Admiral John Kirby, the Pentagon press secretary, said there were no civilian casualties in the operation and all U.S. personnel involved had safely left Libya. The Pentagon declined to discuss further details of the operation and it was not immediately clear whether there were non-civilian casualties.
Until his capture, Khatallah continued to live freely in Libya while giving taunting interviews to major media outlets as recently as six months ago. The State Department designated Khatallah as a terrorist in January, describing him as a leader of Ansar al Sharia, a Libyan militant group that has been described as having links to Al Qaeda.
Benghazi, the hub of Libya’s east, has been beset by turmoil in recent months, and the chaos deepened last month when a rogue ex-general based in the city launched a self-declared war on Islamist armed groups, resulting in more than 100 deaths.
"FULL WEIGHT" OF THE JUSTICE SYSTEM
A U.S. official said Khatallah would be charged and prosecuted through the U.S. court system and would not be sent to the prison for suspected al Qaeda militants in Guantanamo, Cuba.
"Since the deadly attacks on our facilities in Benghazi, I have made it a priority to find and bring to justice those responsible for the deaths of four brave Americans," Obama said, adding that Khatallah would "face the full weight of the American justice system."
A law enforcement official said Khatallah was questioned initially about any new potential terror threats and was then read his Miranda rights. With Khatallah now in custody, prosecutors are likely to submit the case to a federal grand jury, which could bring additional charges.
A criminal complaint released by the U.S. District Court for Washington, D.C., accused Khatallah of killing a person in the course of an attack on a federal facility, providing material support to terrorists and using a firearm in commission of a crime of violence.
An elite American interrogation team will question the suspected ringleader, a U.S. official told Reuters on Tuesday.
The official, speaking on condition of anonymity, did not say whether members of the U.S. High Value Detainee Interrogation Group were already in place to question Ahmed Abu Khatallah.
The inter-agency unit was created in 2009 and is housed in the FBI's National Security Branch. The group specializes in garnering information from suspects to prevent planned terror attacks.
The decision not to send Katallah to Guantanamo follows past practice and is in line with Obama's policy of bringing suspected militants caught abroad through the U.S. justice system rather than trying them in the military tribunal system at Guantanamo Bay, a prison he is trying to close.
"We have used the federal court system to convict and incarcerate hundreds of terrorists," White House spokeswoman Caitlin Hayden said in a statement.
"As to whether (he) will be debriefed for intelligence purposes, I can't comment on the specifics, but as a general rule, we will always seek to elicit all the actionable intelligence and information we can from terrorist suspects taken into our custody."
Trying Khatallah in federal court could be controversial. Republicans have opposed bringing cases involving accused terrorists to civilian courts, and Sens. John McCain (R-Ariz.) and Lindsey Graham (R-S.C.) both said Tuesday that Khatallah should be sent to the military prison at Guantanamo Bay, Cuba.
Lawmakers welcomed Khatallah's capture, but Republicans said they were concerned about whether the administration would take full advantage of the opportunity to interrogate him for his intelligence value.
"I want him to be held a sufficient period of time under the law of war to gather intelligence," said Graham. "We're shutting down intelligence-gathering. Weâre turning the war into a crime, and it will bite us in the butt."
"I think they should take him to Guantanamo," said McCain. "That's why we have the detention facilities and it's totally inappropriate to keep him anyplace else."
But Senator Dick Durbin, (D-Ill.), the Senate's No. 2 Democrat, said Khatallah would stand a better chance of being prosecuted through the criminal justice system, noting that only a handful of people had been tried before military commissions while several hundred had been convicted in federal court.
"It's a tired response from their side," he said of the Republican calls for a transfer to Guantanamo.
After the 2012 attack, which killed Ambassador Chris Stevens, Republicans accused the Obama administration of playing down the role of al Qaeda in the attack for political reasons.
They also said then-Secretary of State Hillary Clinton had failed to take adequate steps to ensure the safety of American diplomatic personnel, an issue that is still resonating as Clinton considers a 2016 presidential bid.
The Libyan government had no immediate comment on the U.S. announcement and it was unclear whether Washington had notified Libyan officials before carrying out the operation.
It was the second time the administration has said U.S. special operations forces have gone into Libya to detain a militant. A U.S. Army Delta Force team grabbed al Qaeda suspect Nazih al-Ragye, better known as Abu Anas al-Liby, in Tripoli in October 2013 and sent him to a U.S. Navy ship for interrogation.
Al-Liby was later charged in a U.S. federal court in New York in connection with the 1998 bombing of the U.S. Embassy in Kenya, which killed more than 200 people.
House of Representatives Intelligence Committee Chairman Mike Rogers, a Republican, called the capture "a little bit of a bright spot in what has not been a great story to tell on the rising tide of terrorism organizations around the world."
He said, however, that the arrest did not break Khatallah's organization and said there were more than a dozen "individuals of interest" that the United States needed to apprehend.
Secretary of State John Kerry said the Sept. 11, 2012, attack was felt "acutely" by the State Department. He welcomed Khatallah's capture, saying: "This bold action by the superb United States military is a clear reminder to anyone who dares do us harm that they will not escape with impunity."
Reuters and the Los Angeles Times contributed to this report