Taliban insurgents had planned to use five Americans detained in Pakistan, who had contacted the militant group through the Internet, to carry out attacks inside the US ally, a police official said on Saturday.
Usman Anwar, police chief in Sargodha, where the men were arrested this month, said emails had also revealed plans for the young men from Virginia to travel to a Pakistani nuclear power plant.
"We believe that they were supposed to be used inside Pakistan," Anwar told Reuters by telephone.
"In their last email to the Taliban, we found they mentioned the Chashma Nuclear Plant and that's why they were going to Mianwali (district)."
Anwar declined to give details because police were still interrogating the suspects.
The case has illustrated how easy it is for anyone to pursue dreams of joining jihad through cyber channels, a worrying reality for Pakistan, already struggling on the ground against Taliban insurgents.
Washington is pressuring Pakistan to root out militants in lawless tribal areas who cross the border to attack Western forces in Afghanistan. But it is a sensitive demand.
Pilotless US drone aircraft attacks on suspected militants on Pakistani soil have infuriated many Pakistanis.
The five men were arrested in Sargodha, home to one of Pakistan's biggest airbases, 190 km (120 miles) southeast of the Pakistani capital Islamabad.
The Americans -- two are of Pakistani ancestry, one of Egyptian, one of Yemeni and one of Eritrean -- have not been charged.
They were found with maps and had intended to travel through northwest Pakistan to an al Qaeda and Taliban militant stronghold on the Afghan border, officials said. Some analysts say the case reflects a new strategy by militants to try to avoid more stringent security measures by setting up networks on the Internet.
The possibility of militants attempting to attack Pakistan's nuclear weapons alarms Western powers, although analysts say it is highly unlikely.
