(Bloomberg) -- President Barack Obama’s administration has pledged to kill or capture the masked Islamic State militant known as “Jihadi John,” who is pictured in videos beheading several hostages including Americans.

Attorney General Eric Holder said on CNN the U.S. “wouldn’t put anything off the table,” including sending military troops, to “hunt” the man. He was identified by the Washington Post Thursday as Mohammed Emwazi, a 26-year-old from London.
“Anyone involved in the killing of American citizens will be held accountable,” Holder said in the interview broadcast Friday. “It doesn’t matter where you are, we will find you. We will hunt you down.”
U.S. intelligence and military officials said that British security officials uncovered Emwazi’s real identity months ago. While the U.S. is allied with the U.K. in seeking to bring him and other extremists to justice, neither country has planned an operation to search him out inside Syria, they said.
Like hostage rescue efforts, the three officials said, the campaign against the extremist group has been hampered by a shortage of timely and accurate on-the-ground and human intelligence on the group’s leaders and public figures such as Emwazi, especially in Syria.

Surveillance

The U.S. keeps surveillance drones in orbit over areas where the extremists congregate, but the intelligence they provide is necessarily limited, the officials said.
Speaking on the condition of anonymity to discuss classified intelligence, the officials said the best chance to capture or kill Emwazi and others is likely to come if they venture outside IS-controlled areas of Syria and Iraq, or if they are careless in using radios, computers or mobile phones.
So far, though, said one of the officials, the group has been good at protecting its communications and has largely retreated from moving in open country, where its vehicles are vulnerable to drone strikes.
Holder spoke to CNN in one of several interviews granted as he prepares to leave office next month once the U.S. Senate confirms his successor. His sentiments about the need to bring the masked jihadist to justice are shared by his boss, Obama, who made the call to send U.S. Navy SEALs to kill al-Qaeda leader Osama bin Laden in Pakistan in 2011.

Obama Vow

“Any time any American is harmed anywhere in the world, the United States government is going to to be going after that person,” Obama said Thursday in a televised interview with KOMO-TV in Seattle. “And eventually, if you hurt an American, you’re going to be brought to justice in some fashion.”
Both Obama and Holder declined to confirm the identity of the masked militant or comment on the specific case.
White House Press Secretary Josh Earnest said Thursday that U.S. intelligence officials had “zeroed in on an individual” at the end of 2014 by working with British allies and that “the investigation is one that we are pursuing rather aggressively.”
“The United States’ commitment and the president’s commitment to ensuring that we find and hold accountable the terrorists who are responsible for the murders of American citizens has never been stronger,” Earnest said.

Hostage Killings

Emwazi, who was born in Kuwait, grew up in London in a well-to-do family and graduated from college before joining the Islamic State group in Syria, the Washington Post reported. He has appeared in a series of videos making threats against Americans and killing hostages including American journalists James Foley and Steven Sotloff, British aid worker David Haines, British taxi driver Alan Henning and U.S. aid worker Peter Kassig.
Holder told CNN he worries about a “lone-wolf” terrorist attack taking place within the U.S and urged shopping malls to increase their security measures to protect their customers.
Obama will speak at a Justice Department event Friday honoring Holder’s six-year tenure. Loretta Lynch, the top federal prosecutor in Brooklyn and Obama’s nominee to replace Holder, is expected to be confirmed by the U.S. Senate next month.
Among Holder’s other media interviews, he told Politico that the standard of proof required to bring civil rights charges is too strict and should be altered.
Under Holder, the Justice Department investigated several high-profile cases for possible civil rights violations, including the shooting deaths of Florida teenager Trayvon Martin by a neighborhood watch volunteer and 18-year-old Michael Brown by a Ferguson, Missouri, police officer.
The Department said on Tuesday that it would not bring charges against George Zimmerman, who shot Martin. Holder has said he would complete the investigation into the Ferguson shooting, which led to nationwide protests, before he leaves office.
To contact the reporters on this story: Toluse Olorunnipa in Washington at tolorunnipa@bloomberg.net; John Walcott in Washington at jwalcott9@bloomberg.net
To contact the editors responsible for this story: Joe Sobczyk at jsobczyk@bloomberg.net Elizabeth Wasserman