Indonesian police detained six people on Saturday, including a 10-year-old girl, on suspicion that they planned to travel to Syria to join Islamic State, a police spokesman said.

News website detik.com reported that Jakarta police detained the Indonesians, originally from Makassar in South Sulawesi, as they were about to take a flight from the capital's main airport to Doha.

The six, ranging in age from 10 to 48 years old, have not been charged with a crime and could not immediately be reached for comment.

It was not clear whether the members of the group were related.

National Police spokesman Agus Rianto told Reuters the police also questioned a man at a Jakarta guesthouse where the six had been staying.

Security officials and analysts estimate that dozens of citizens from Indonesia, which has the world's largest Muslim population, may have joined Islamic State in Syria or Iraq.

Malaysian and Indonesian militants have also discussed forming a 100-strong Malay-speaking Islamic State unit in Syria, according to a report from a security group.