ISLAMABAD: Pakistani police are pursuing terrorism charges against five detained American men, police said on Friday, a move that could complicate efforts to bring the men back to the United States where they could also land in the courts.

The case has bolstered fears that Americans and other Westerners are heading to Pakistan to link up with Al-Qaeda and other militant groups, and it could test a US-Pakistani relationship already made brittle by demands of the war in neighboring Afghanistan.

The young Muslim men, who are from the Washington, D.C., area, have not yet been formally charged with any crime.

However, police are now alleging that the men were collecting and attempting to collect material to carry out terrorist activities in the list of recommended charges to be presented to a court, police official Nazir Ahmad said.

Those charges fall under sections of Pakistan’s anti-terrorism law, and the punishments range from seven years to life in prison.

The men appeared before a magistrate in the Punjab province town of Sargodha on Friday. Police were given 10 more days to hold them and further investigate, said Ansar Ahmad, another Sargodha police official. The five were arrested in Sargodha earlier this month.

Pakistani officials have said those detained included two Pakistani-Americans, two Ethiopian-Americans and an Egyptian-American named Ramy Zamzam who is a dental student at Howard University in Washington.

The others were identified as Waqar Hussain, Aman Yamar, Ahmad Abdul Minni and Umer Farooq.