A Pakistani-American and his son have been arrested in the US after the son admitted attending an al-Qaeda training camp in Pakistan, officials say.
Umer Hayat has been accused of lying about his son's activities
They say that Umer Hayat and his son Hamid are now being questioned by the Federal Bureau of Investigation (FBI) in the Californian capital, Sacramento.
Hamid Hayat has allegedly confessed to planning attacks on US institutions.
They are now being held on charges of lying to the authorities and violating the terms of their visas.
The father and son were arrested in their home town of Lodi, 60kms (38 miles) south of Sacramento.
Relatives deny that either man has been involved in any kind of terrorism.
They say that Hamid Hayat is more interested in cricket than politics.
But the FBI affidavit quotes him as telling agents that he attended an al-Qaeda training camp in Pakistan for about six months in 2003 and 2004.
"Hamid further stated that he and others at the camp were being trained on how to kill Americans," the affidavit said.
"Hamid advised that he specifically requested to come to the United States to carry out his jihad mission," the document said.
The affidavit says that potential targets included hospitals and large food stores.
The affidavit further quotes 22-year-old Hayat as saying that photos of President Bush and other American political figures were pasted onto targets during weapons training.
It says that at the end of training, participants were given the opportunity to choose the nation where their attacks would be carried out.
Umer Hayat is accused of lying about his son's involvement in terrorism.
At least two other Muslims from Lodi have also have been detained on immigration violations.
Correspondents say that the US has launched numerous terrorism prosecutions since the September 2001 attack on the World Trade Centre, although many of these cases have fizzled out.