Police are trying to determine whether five Americans detained in Pakistan had planned to attack a complex that houses nuclear power facilities, authorities said Saturday.

The young Muslim men, who are from the Washington, D.C., area, were picked up in Pakistan earlier this month in a case that has spurred fears that Westerners are traveling to the South Asian country to join militant groups.

Pakistani police and government officials have made a series of escalating and, at times, seemingly contradictory allegations about the men's intentions, while U.S. officials have been far more cautious, though they, too, are looking at charging the men.

A Pakistani government official alleged Saturday that the men had established contact with Taliban commanders and planned to attack sites in Pakistan. Earlier, however, local police accused the men of intending to fight in Afghanistan after meeting militant leaders.

The men had a map of Chashma Barrage, a complex that along with nuclear power facilities houses a water reservoir and other structures, said Javed Islam, a senior police official in the Sargodha area of Punjab province. He stressed that the men were not carrying a specific map of any nuclear power plant, but rather the whole of Chashma Barrage.

The detained men also had exchanged e-mails about the area, Islam said.

"We are also working to retrieve some of the deleted material in their computers," he said.

Pakistan has a nuclear weapons arsenal, but it also has nuclear power plants for civilian purposes.

It began operating its first nuclear power station with Canadian assistance in 1972. It has not signed the Nuclear Non-Proliferation Treaty, the main international agreement meant to stem the spread of nuclear weapons technology.

China helped Pakistan build the nuclear plant at Chashma, about 125 miles (200 kilometers) southwest of the capital, Islamabad. Work on a second nuclear power plant is expected to be completed in 2011.

Any nuclear activity in Pakistan tends to come under scrutiny because of the South Asian nation's past history of leaking sensitive nuclear secrets due to the actions of the main architect of its atomic weapons program, Abdul Qadeer Khan. But as militancy has spread in Pakistan, officials have repeatedly insisted that the nuclear weapons program is safe.

Pakistani police plan to recommend that courts charge the five men with collecting and attempting to collect material to carry out terrorist activities in Pakistan, police official Nazir Ahmad told The Associated Press. The punishments for those charges range from seven years to life in prison, he said.