Indonesian police say three workers of US oil and gas giant ExxonMobil who had been abducted in Aceh province have been freed.

An Aceh police spokesman said the hostages were unharmed and probably with their families by now. Police were still investigating the details of their release and whether any ransom had been paid.

The workers were abducted on Thursday on their way home from work. Police blamed the abduction on Aceh separatist rebels.

The incident comes before the expected signing of a peace agreement between the Indonesian government and the rebels on December 9.