By Dominic Hughes BBC correspondent in Sydney

Police in Australia have raided the homes of at least 10 Iranian families suspected of supporting an opposition group that is listed as a terrorist organisation.

The Australian federal police say the raids are part of an on-going investigation.

The raids took place in the early hours of the morning in the cities of Melbourne, Sydney and Brisbane.

Witnesses said that police removed documents and also some computer equipment.

The Australian federal police would not comment on the details of the operation but did confirm that search warrants were issued for 10 properties.

It is believed the homes belonged to Australian-based supporters of an Iranian opposition group, the People's Mujahideen.

The group is listed as a terrorist organisation by the governments of both Australia and the United States.

But a member of one of the families that was raided said the group were freedom fighters and formed a valid opposition to the ruling Islamic government in Tehran.

After last year's bombing in Bali, similar raids were carried out on the homes of suspected Islamic militants.