Sunderland Area Command Superintendent Alan Veitch said: "What happened on Tuesday, July 23, was a tragic accident and our thoughts and sympathies are with the family and friends of Chloe Fowler and Toni-Beth Purvis.
"The loss of any life is horrendous but the tragic deaths of these two young girls was particularly devastating for everyone involved.
"The circumstances emergency services faced at the scene that evening were extremely dangerous and challenging, with that particular section of the River Wear being fast flowing and filled with hidden hazards.
"Those who helped in the search for the two girls did everything they could to try and save them and I'd like to thank everyone who assisted in the search operation for their brave efforts.
"The role of an emergency service worker - be it police, fire or ambulance - is filled with difficult situations and challenges however the loss of a young person's life is, and will always be, particularly distressing."
More top news
Maggie Thompson says she is devastated at the continued vandalism to her daughter Siobhan's grave, following her death in 1991.
The department chain has announced plans of a 45 day consultation, in which the amount of redundancies could be decided.
Stephen Unwin and William McFall were handed whole life sentences for the brutal murder of 28-year-old Quyen Ngoc Nguyen last August.