Sydney: Australian police are investigating claims officers used excessive force when arresting teenagers allegedly planning an Daesh-inspired terrorist attack in the southern city of Melbourne, authorities said on Monday.

More than 200 police were involved in a series of predawn raids Saturday following a monthlong sting operation. Five men aged 18 and 19 were detained.

Victoria Police Acting Chief Commissioner Tim Cartwright said he had seen complaints from two families about the conduct of police during the raids, and that one formal complaint about misconduct would be investigated.

“My understanding was that OC [pepper] spray was used on at least one of the men and there was resistance there,” Cartwright told reporters.

“There would routinely be forced used to some degree. We seek to immobilise the person to make sure they don’t have access to weapons,” he said.

Police, who seized knives and swords during the raids, said the attack was being planned to coincide with centenary services commemorating Australia’s role in the battle of Gallipoli during the First World War.