Jakarta – Indonesia's military has warned rebels in Aceh province to free five hostages, including a local TV crew, by a Tuesday evening deadline or face attack, an army spokesman said.

Separatists of the Free Aceh Movement (GAM) kidnapped the five more than a week ago while they were travelling through a rebel stronghold in the east of the province. The hostages include a reporter and a cameraman from private broadcaster RCTI. The military has been searching for the hostages since then, and it was unclear if they now knew their location.

"They should not use the hostages as their weapons, their shields. Saving [the hostages] would be the purpose of this operation," said Lieutenant Colonel Ahmad Yani Basuki, a spokesman at a key military base in the Acehnese city of Lhokseumawe. He gave no details on what the military planned if the hostages were not released by the 6pm deadline.

On Sunday, GAM invited a small group of local reporters to where they are holding the five to show they were healthy. Two are wives of soldiers, whom the station rents housing from. Basuki said there had been no talks between the military and GAM over the incident.

Indonesia's military has been waging a fresh campaign in Aceh since May 19 to crush the rebels after peace talks failed to end a war that has killed 10,000 people since 1976.

More than 400 people, mostly rebels, have been killed in the latest offensive, the military has said. On Monday, troops killed at least eight rebels and found five unidentified dead bodies across the region on the northernmost tip of Sumatra island. The offensive has also led to curbs on foreign media in Aceh.

In the local capital Banda Aceh, police said a dossier against American freelance journalist William Nessen had been submitted to prosecutors, bringing him closer to trial over alleged immigration offences.

Nessen was arrested in late June after he surrendered to the military following more than a month travelling with GAM. The New York-based Committee to Protect Journalists said in a statement that conditions for the media in Aceh were going from bad to worse.

Last week government troops kicked and beat an Indonesian radio reporter in South Aceh. Basuki said the reporter angered a soldier who later slapped him. The soldier had been punished by his superiors but would not go on trial, Basuki said.