It happened on the canal towpath in the woods between 1.45pm and 2.15pm.
A member of the public called police after a man approached him to say he had been robbed by men with knives.
A 16-year-old boy and a 20-year-old man were arrested nearby.
Detectives now want to speak to the victim of the robbery and are appealing for the man to come forward.
They are also keen to speak to any witnesses.
Detective Sergeant Khan, of Leeds CID, said: “Although no victim has come forward yet, we are appealing to trace the man involved who alerted the member of the public.
“There is no suggestion anyone was injured in this incident, and our enquiries remain ongoing in the area and to determine if a robbery took place.
“I would appeal for anyone with information or anyone who witnessed any suspicious behaviour in the area to get in touch."
Anyone with information is aked to contact Leeds CID on 101, quoting reference 13190174028.