A BOAT has been cordoned off after a Southampton boy, 17, and girl, 12, died off of Bournemouth beach.

Police officers have been spotted by the Dorset Belle boat at a harbour in Poole today.

Offices "guarded" the boat and forensic teams were also in the area.

A 17-year-old boy from Southampton and 12-year-old girl from Buckinghamshire died yesterday evening following an incident at the beach.

Eight other people were injured and a man, who was on the water at the time, was arrested on suspicion of manslaughter.

READ MORE: Beach tragedy survivor, 18, from Southampton 'was stuck in riptide', says dad

The boat, which operates a popular excursion tour at Dorset’s pier, is under police cordon.

The Sun reported that a police source said: "This vessel is under a police cordon. No one is permitted onboard or to touch the vessel.”

MP for Bournemouth East, Tobias Ellwood, has called for Dorset Police to release more information surrounding the tragedy.  He said: "This is a tragic incident and the police clearly have to do their investigation and that is understood. 

"But I would encourage them to give more clarity as to the general details of this tragedy to help assure beachgoers that this occurrence is unlikely to happen again. 

"It will place this event into context while reassuring people that it is safe to visit our beautiful beaches."