Last Updated at 2:52 p.m. EST
Pakistani intelligence agents have arrested Adam Gadahn, the American-born spokesman for al Qaeda, in an operation in the southern city of Karachi, the Associated Press and Pakistani media reported today.
U.S. officials have not confirmed the arrest of the California native for whom a $1 million reward has been posted.
Reports of the arrest of Gadahn follow recent detentions of several Afghan Taliban commanders in Karachi, which have been viewed as a sign that Pakistan is cooperating more closely with Washington in its fight against insurgents.
Two officers who took part in the operation, and who spoke on condition of anonymity because they were not authorized to release the information, told CBS News' Farhan Bokhari that Gadahn was arrested in the sprawling southern metropolis in recent days. A senior government official confirmed the arrest, also on condition of anonymity.
Gadahn, who is also known by various aliases, including Yahya Majadin Adams and Azzam al-Amriki, grew up on a goat farm in Riverside County, California, and converted to Islam at a mosque in nearby Orange County.
Gadahn moved to Pakistan in 1998, according to the FBI, and is said to have attended an al Qaeda training camp six years later, serving as a translator and consultant for the group. He has been wanted by the FBI since 2004, and there is a $1 million reward for information leading to his arrest or conviction.
He has posted videos and messages calling for the destruction of the West and for strikes against targets in the United States. The most recent was posted Sunday,.
A U.S. court charged Gadahn with treason in 2006, making him the first American to face such a charge in more than 50 years. He could face the death penalty if convicted. He was also charged with two counts of providing material support to a designated foreign terrorist organization.
In the 25-minute video posted on militant Web sites Sunday, Gadahn described Maj. Nidal Hasan as a pioneer who should be a role model for other Muslims, especially those serving Western militaries.
"Brother Nidal is the ideal role-model for every repentant Muslim in the armies of the unbelievers and apostate regimes," he said.
Gadahn was dressed in white robes and wearing a white turban as he called for attacks on what he described as high-value targets.
"You shouldn't make the mistake of thinking that military bases are the only high-value targets in America and the West. On the contrary, there are countless other strategic places, institutions and installations which, by striking, the Muslim can do major damage," he said, an assault rifle leaning up against a wall next to him.
Hasan has been charged in the Nov. 5 shooting that killed 13 people at Fort Hood, Texas. The 39-year-old Army psychiatrist remains paralyzed from the chest down after being shot by two civilian members of Fort Hood's police force.
In the latest video, Gadahn said those planning attacks did not need to use only firearms. "As the blessed operations of September 11th showed, a little imagination and planning and a limited budget can turn almost anything into a deadly, effective and convenient weapon."
CBS News' Farhan Bokhari reports more about Gadahn's arrest.
Pakistan's inter-services intelligence (ISI) spy agency, run by the country's military and backed by information from the CIA, has arrested a key militant associated to Al Qaeda's top leaders, during a raid in the southern city of Karachi, a Pakistani security official and a Pakistani government official told CBS News on Sunday.
Pakistan's privately run GEO TV named the arrested individual as Abu Yahya Azam and described him as "a close accomplice" of bin Laden. A security official who spoke to CBS News on the condition of anonymity said, the arrested man was Adam Yahiye Gadahn - an Al-Qaeda militant for whom the FBI has offered U$1m as a reward for information leading to his arrest. The government official who also spoke on condition of anonymity confirmed Gadahn's arrest and said "this is a major development."
The FBI's Web site lists some of Gadahn's aliases as; 'Abu Suhayb Al-Amriki, Abu Suhail Al-Amriki, Abu Suhayb, Yihya Majadin Adams, Adam Pearlman, Yayah, Azzam the American and Azzam Al-Amriki'.
The FBI's Web site describes Gadahn for being "indicted in the Central District of California for treason and material support to Al Qaeda. The charges are related to Gadahn's alleged involvement in a number of terrorist activities, including providing aid and comfort to Al Qaeda and services for Al Qaeda".
A western defense official from a NATO member country based in Islamabad, responding to news of the arrest told CBS News on condition of anonymity, Gadahn's capture will "make it the first time [since the Sept. 11 terrorist attacks] that Osama bin Laden could be in danger of being taken dead or alive some day."
The western defense official said the arrest at the very least confirms that Pakistan's intelligence services as well as U.S. intelligence "had successfully penetrated Al-Qaeda and the Taliban and the fruit of that penetration is coming out in the shape of significant arrests."
Pakistan's intelligence services working in association with the CIA have had a string of successes since last month, when Mullah Abdul Ghani Baradar, the Taliban military chief in Afghanistan, was arrested during a raid just outside Karachi.
At least four other senior Taliban militants, subsequently named as Mullah Abdus Salaam, Mullah Kabir, Mullah Mohammad and Mullah Amir Muawiya, were also arrested.
A second Pakistani security official who also spoke to CBS News on condition of anonymity said at least half of the 18 members of the top Taliban council known as the "shura," presided over by Mullah Mohammad Omar, were now in custody of Pakistan's intelligence services. "Now, Gadahn's arrest may begin opening the doors which lead to Al-Qaeda related figures" said the second Pakistani security official.