A Finnish court has thrown out charges against Iraqi twin brothers of taking part in Islamic State-related killings of at least 11 unarmed soldiers.

The Pirkanmaa District Court says the two who were not identified, were set free on Wednesday.

The court in Tampere, southern Finland, said the evidence against them was too weak. It included testimonies from other asylum-seekers, a video footage of the massacre by IS militants and information from an Iraqi investigative commission.

State prosecutors had demanded life sentences and claimed the brothers took part in atrocities committed by IS militants at a military base outside Tikrit in June 2014 when some 1,700 Iraqi army soldiers were slain.

The brothers arrived in Finland in September 2015 and were arrested three months later.