ISLAMABAD, Pakistan — An operative of al-Qaida believed to be an American was arrested in the sprawling southern city of Karachi in recent days by Pakistani security officials, the New York Times reported Sunday, citing Pakistani officials.
U.S. and Pakistani officials said the man arrested was Abu Yahya Mujahdeen al-Adam, who was thought to be affiliated with al-Qaida fighters in Afghanistan.
Initial reports seemed to have confused him with Adam Gadahn, a California native who has been an al-Qaida spokesman and often appears on videos calling for strikes against targets in the United States.
U.S. and Pakistani officials later said the man being held was born in Pennsylvania.
One U.S. official briefed on the arrest described the operative in custody as fair-skinned and someone who spoke both English and Pashto.
Little else was known about him, U.S. officials said, and it was not immediately clear that U.S. officials were involved in the arrest. There was no confirmation that the arrested man was in fact an American.
Senior administration officials said on Sunday that they did not believe the arrest was of Gadahn. For hours, information was difficult to confirm from Pakistan. President Barack Obama was briefed on news reports of the arrest, but later learned they were most likely not correct.
Gadahn has been on the FBI's most wanted list since 2004 with a $1 million reward for information leading to his capture, and he is the first American to be charged with treason in more than half a century. He was believed to have been operating in the area of the Pakistani-Afghan border.
In a recent video, Gadahn urged Muslims to follow the example of Maj. Nidal Malik Hasan, the American charged with the shooting that killed 13 people in Fort Hood, Texas, in November.
While the importance of the latest arrest was not clear, it builds on the capture of several senior Afghan Taliban leaders in recent weeks, including Mullah Abdul Ghani Baradar, the No. 2 official in the Afghan Taliban leadership.
A senior Obama administration official in Washington said that Pakistani authorities had Baradar in custody and still allowed American interrogators to question him regularly.
"He's talking to us but we're still in the trust-building phase," the official said, speaking to the New York Times on condition of anonymity because the interrogation results are confidential. "He's not giving us any actionable intelligence."
The official said that Pakistani authorities were likely to have more leverage over Baradar than U.S. officials, because of the longstanding relationship between the Taliban and Pakistan's main spy agency, the Inter-Services Intelligence Directorate. U.S. officials also assume that the ISI tends to some of Baradar's family members.
The officials discounted the likelihood that Pakistani authorities were using harsh interrogation methods on Baradar. "They know what he knows," the official said.
The arrest of Baradar and about a half-dozen other senior Afghan Taliban leaders in Pakistan in recent weeks have prompted some analysts to declare that the Pakistani intelligence service has committed itself to working against the Afghan Taliban, its longtime proxy against Indian interests in Afghanistan. But the senior administration official voiced skepticism that there had been any strategic shift by the highest levels of the Pakistani spy agency.
"It's still not clear what's going on, but we haven't concluded there's some major shift," the official said.