One of the men, Michael Ray Stubbs, worked as a heating and air conditioning technician at the Lawrence Livermore National Laboratory — a major nuclear weapons lab outside San Francisco, California — for about 10 years ending in 2000. Officials said the FBI was looking into whether he had access to sensitive information.
Michael Ray Stubbs, 55, and his brother James, 56, a convert to Islam, were arrested on immigration violation charges Dec. 13 in the town of Tanza in Cavite province, 21 miles southwest of Manila, the Bureau of Immigration said.
The brothers denied any wrongdoing when they appeared at a news conference in handcuffs.
Immigration Commissioner Andrea Domingo told reporters Tuesday that James Stubbs met with members of the Abu Sayyaf Muslim extremist group, as well as the Moro Islamic Liberation Front separatist movement, two groups loosely linked by Philippine officials to al Qaeda.
"These are all fabricated lies," James Stubbs shouted as Domingo addressed the news conference.
An irritated Domingo responded: "This is the Philippine government. They're violating immigration laws and they're being charged and they are going through immigration proceedings."
The brothers, born in the U.S. state of Missouri, would be deported to the United States as "undesirable aliens ... based on intelligence reports that they were seen meeting with known leaders of various terrorist cells in the country with links to al Qaeda," the immigration bureau said.
Domingo said they were under surveillance before their arrest.
The two had tourist visas but also carried documents indicating they were soliciting funds for the construction of Muslim schools and mosques, Domingo said.
She said there was no evidence linking the two to any past or planned terrorist plots, but said James Stubbs allegedly called for the overthrow of the U.S. government in statements to local authorities.
James Stubbs said he has a Filipino wife and was in the Philippines because she was pregnant.
A naval intelligence officer, speaking on condition of anonymity, said U.S. officials were concerned that Michael Ray Stubbs may have passed sensitive information from Livermore to his brother.
Susan Houghton, a spokeswoman for the Livermore lab, confirmed that Michael Ray Stubbs used to work there for about 10 years until 2000.
"We have been working closely with the FBI on this issue since he was arrested in the Philippines a few weeks ago," she said.
She said Stubbs' clearance was terminated after he left on medical leave in March 2000.
The U.S. Embassy declined to comment on the allegations. Spokeswoman Karen Kelley said she understood the brothers retained legal council to address the charges.
According to Philippine military intelligence reports, James Stubbs left his job as a teacher in California to study Arabic in Sudan. He met in May with several charity groups suspected of being al Qaeda fronts and founded by Mahmoud Afif Abdeljalil — believed to be a close associate of Osama bin Laden's brother-in-law.
Abdeljalil was arrested in September in the southern Philippine city of Zamboanga on charges of having an expired visa. After he was interrogated, he was ordered deported.
The charities were not immediately identified, but the immigration bureau said they were used to channel funds to al Qaeda cells in the Philippines.