Police say the girls - aged 10 and 11 - reported being touched inappropriately by a man while in the water near the pier.

Officers attended the scene after receiving a report in the area of Pier Approach around 3.45pm on Sunday afternoon.

Following enquiries by police, a 43-year-old man from London was arrested on suspicion of sexual assault.

Detective Constable Cameron Carter, of Dorset Police, said: "We are carrying out a detailed investigation into these incidents and I am keen to hear from anyone who witnessed what happened who has not already spoken to police.

"I would also urge anyone with relevant mobile phone footage to please get in touch."

The force said local officers would be carrying out proactive patrols of the beach and the surrounding area.

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Earlier this month, on 17 June, police were called to Bournemouth seafront after a man allegedly attempted to sexually assault a teenage girl outside a fish and chip shop.

A 30-year-old man from London was arrested on suspicion of attempted sexual assault and attempted assault.

On the same day, a 17-year-old boy claimed he was sexually assaulted by a man in the water near Bournemouth pier.

Police have not made an arrest in relation to the allegation.