The students, in their 20s and from the US state of Virginia, were detained in December in the town of Sargodha, 190 km southeast of Islamabad, and accused of contacting militants over the Internet and plotting attacks.

They have not been formally charged, but police on Tuesday submitted a charge sheet in an anti-terrorist court in Sargodha, said defence lawyer Hassan Dastagir.

"The court received the challan (charge sheet) which carries charges of criminal conspiracy, having the intention to go to Pakistan's neighbouring countries to topple the government and involvement in fund raising for terrorist acts," he said.

The court is expected to formally charge the five at the next hearing on Mar 10, he said.

The case has raised alarm over the danger posed by militants using the Internet to evade tighter international security measures and plan attacks.

The five, who earlier told the court they only wanted to provide fellow Muslims in Afghanistan with medical and financial help, face life imprisonment if convicted, Dastagir said.

Police have said the men - two of them of Pakistani origin, one of Egyptian, one of Yemeni and one of Eritrean origin - wanted to go to Afghanistan to join the Taliban to fight Afghan and Western forces.

Police have said emails showed they contacted Pakistani militants who had planned to use them for attacks in Pakistan, a front-line state in the US-led war against militancy.

The five have accused the US Federal Bureau of Investigation and Pakistani police of torturing them and trying to frame them. Pakistani authorities deny the accusations of mistreatment.