Sargodha: A group of detained young Americans were grilled by the FBI in Pakistan after reports that they had tried to join Islamist militant groups and travel to the northwest Taliban heartland, officials said on Friday.
US President Barack Obama vowed an investigation into how and why the five men left the United States for Pakistan, possibly swept up in extremist movements in a country battling to contain militant organisations.
The five young men arrested on Wednesday in Sargodha, about 180 kilometres (110 miles) south of Pakistan`s capital Islamabad, were US citizens with origins in other countries, including two Pakistani-Americans, officials said.
Police officials had said the five men were planning to strike "sensitive installations" in Pakistan, but a picture formed on Friday of young Muslim men radicalised by jihadist websites without concrete ties to a specific group.
"They tried to contact jihadi groups in Pakistan through YouTube and other websites," Sargodha district police chief Usman Anwar told a local TV station.
"From the documents and maps that they were carrying, it appeared that their destination was Miranshah, the main town of North Waziristan tribal district. This indicates what they were up to."
North Waziristan is one of seven tribal districts along the Afghan border, where al-Qaida, Taliban and other militant groups have carved out sanctuaries and training camps in the hostile region outside direct government control.
In an interview with CNN broadcast on Thursday, Anwar said: "They were there for jihad... They could have done anything. They had US passports. They would have access to many, many places."
The arrests have raised fears that Muslim radicalisation is gaining momentum in the United States, creating high-value recruits for Islamist groups.
While Obama declined to speak specifically about the arrests, he vowed a full investigation.
"There will undoubtedly be a series of investigations surrounding these events, so I`d prefer not to comment on them at this point," Obama told reporters in Oslo on Thursday as he collected his Nobel peace prize.
He warned of the relative ease with which members of the Muslim American community can gain access to distorted and extremist teachings on the Web.
"We have to constantly be mindful that some of these twisted ideologies are available over the Internet and can affect our young people," he said.
A Muslim group in the United States said the men went missing from their homes in northern Virginia late last month.
The Council on American Islamic Relations said families of the missing men had asked for their help and provided a farewell video showing one of the five men delivering a "final statement" that included war images and Koranic verses.
US assistant secretary of state Philip Crowley said a US embassy team, including at least one agent from the FBI and an officer from the State Department`s regional security office, met the five detainees in Sargodha.
"All we really know is that these individuals were in the United States until recently. They made their way to Pakistan. And beyond that... we are trying to talk to them, find out... what they were up to, what the implications are," Crowley told reporters in Washington.
Asked if the US government had talked to Islamabad about extraditing or bringing the five back to the United States, Crowley replied: "Not to my knowledge. Not yet."
Pakistani authorities said that two of the men were Pakistani-Americans, while the others were Egyptian, Ethiopian and Eritrean, with US citizenship.
Anwar said police also arrested the father of the two Pakistani-American brothers aged 22 and 25 years, who is also an American national but had been living in Pakistan for years.
The FBI in a statement confirmed US citizenship for four of the five who disappeared from the Washington area.
Pakistan is in the grip of a fierce insurgency by Islamist extremists, with more than 2,680 people killed in attacks since July 2007.