Hamid Hayat, 23, and his father, Umer, of Lodi, California, east of San Francisco, were taken into custody over the weekend. Both men are being held on charges of lying to federal authorities.
Two other men were arrested in Lodi for violating terms of their visas, said Immigration and Customs Enforcement spokesman Dean Boyd on Wednesday.
The men have been identified as Muhammad Adil Khan - an imam at the Farooqia Islamic Centre - and Shabbir Ahmed, who is also an imam in Lodi, an administration source said.
Training in Pakistan
According to an FBI affidavit, Hamid Hayat told agents he attended al-Qaida training camps in Pakistan in 2003 and 2004.
"Hamid advised that he specifically requested to come to the United States to carry out his jihad mission," according to the affidavit. "Potential targets for attack would include hospitals and large food stores."
Hayat told agents the camp provided paramilitary training, including training in explosives and hand-to-hand combat, the affidavit stated.
"Hamid further stated that he and others at the camp were being trained on how to kill Americans"
During weapons training, photos of high-ranking US political figures, including President George Bush, were pasted onto targets, according to the affidavit.
"Hamid further stated that he and others at the camp were being trained on how to kill Americans," the affidavit stated.
Hayat, whose US-bound flight from Korea was diverted on 29 May to Japan because his name appeared on a no-fly list, had originally denied any involvement in terrorism.
After the plane was diverted, Hayat was interviewed by an FBI agent, the affidavit said. Hayat denied having any connection to terrorism or terrorist activities and was allowed to continue his travel to the United States, it said.
Some Muslims in the US say they
have been persecuted since 9/11
Upon his arrival in California, Hayat again denied being involved in training camps.
One day later, after taking a lie detector test, Hayat admitted that he had attended an al-Qaida training camp, the affidavit said.
Hamid Hayat's father, Umer, had originally denied that his son was involved in terrorist training camps and had said he knew of no such camps in Pakistan.
After he was shown a videotape of his son admitting that he trained at the camp, Umer said he had visited the camps and had paid for Hamid's flight to Pakistan to attend the training camp.