Read the indictment (pdf).
Miami (CNN) -- Two South Florida imams and a third family member were arrested Saturday on charges of providing support to the Pakistani Taliban, the Justice Department said.
In addition, three others in Pakistan were also indicted on the same charges.
FBI agents arrested Hafiz Khan and his son Izhar Khan in South Florida, the department said. They are expected to make their initial court appearance in federal court Monday.
Another of Hafiz Khan's sons, Irfan Khan, was arrested in Los Angeles and will appear in court there.
Also charged are three Pakistani residents: Ali Rehman, Alam Zeb and Amina Khan. Amina Khan is Hafiz Khan's daughter, and Zeb is his grandson.
The four-count indictment alleges that all six defendants conspired to provide material support to a conspiracy to kill, injure and kidnap people abroad, and that they provided support to the Pakistani Taliban.
Hafiz Khan is the imam at Flagler Mosque in Miami. Izhar Khan is an imam at the Jamaat Al-Mu'mineen Mosque in Margate, Florida.
The indictment and arrests were not linked to the May 2 killing of Osama bin Laden in Pakistan, two U.S. officials said. The charges relate to alleged crimes committed between 2008 and 2010.
"Despite being an imam, or spiritual leader, Hafiz Khan was by no means a man of peace. Instead, as today's charges show, he acted with others to support terrorists to further acts of murder, kidnapping and maiming," U.S. Attorney Wilfredo A. Ferrer said. "But for law enforcement intervention, these defendants would have continued to transfer funds to Pakistan to finance the Pakistani Taliban, including its purchase of guns."
The charges were the result of a three-and-a-half-year investigation, and federal authorities became suspicious by the number of financial transactions between the United States and Pakistan, authorities said.
"They went out of their way to disguise their transactions," Ferrer said.
Authorities said their investigation focused on the mosque leadership.
The indictment describes a number of occasions where Hafiz Khan transferred money to Pakistan, and where money was withdrawn once there.
"Khan solicited and distributed funds for the Pakistani Taliban, both personally and on behalf of others, and worked with the co-defendants and others to support the Pakistani Taliban's jihad," the indictment states.
The court documents also list several conversations between Hafiz Khan and the other defendants where he calls for attacks against the Pakistani government and inquires whether money had been delivered to the Pakistani Taliban.
The elder Khan also built a madrassa in Pakistan's Swat Valley that provided shelter for the terrorist group, the indictment states.
"The main defendant Khan operated and controlled a madrassa to shelter members of the Pakistan Taliban and to train children to become military fighters for the mujahideen," Ferrer said.
He said authorities are aware of several unindicted co-conspirators in the United States and Pakistan.
"You can purchase in Pakistan a gun for as little as $10. He had money coming from all sources," Ferrer said. "More evidence will come forth as the investigation continues."
Yazid Ali, president of the Jamaat Al-Mu'mineen Mosque in Margate, Florida, said his worshippers were shocked by the news. They are cooperating with authorities, he said.
"I would like everyone to know that Masjid Jamaat Al-Mu'mineen does not support terrorism, for this is forbidden in Islam. The Quran clearly tells us do not spread corruption on earth," Ali said. Masjid is Arabic for mosque.
He added that the mosque has received threats, prompting a police car to be stationed in the parking lot.
Nezar Hamze, executive director of Florida's Council on American-Islamic Relations, told CNN that he is concerned about possible fears the charges might stir in the community, even though authorities emphasized their investigation had nothing to do with Islam or the mosques themselves.
"The teaching of Islam in any way shape or form does not financially support terrorism," Hamze said. "These allegations would be completely against Islam."
He said he has been to the two mosques in question and that he's listened to the imams at the services. "You never hear anything being preached like what's being reflected in these charges," Hamze told CNN.
Outside Khan's Miami mosque on Saturday, one worshipper, Obeid Akhtar, expressed suprised to hear the news of the indictment.
"We never heard anything about this," he told CNN. "We are shocked."
The Pakistani Taliban represent a confederation of Taliban groups in northwestern Pakistan, where they are based, said Bill Roggio, military affairs analyst who is managing editor of The Long War Journal.
Those fighters attack targets in Pakistan and across the border in Afghanistan.
The group, which is headquartered in Quetta, is different from the Afghan Taliban, which has been focused on re-establishing the Islamic Emirate in Afghanistan.
Both groups swear allegiance to Taliban leader Mullah Omar and have close ties to al Qaeda, he said.
CNN's Jeanne Meserve, Susan Candiotti, Rich Phillips and Michael Martinez contributed to this report.