Humberside Police have said they are considering the possibility that the "mosque was targeted for racial reasons," but stressed that it would not be fair to speculate on this at present.
They said there was was "no suggestion" of a link between two separate offences - a fire at the mosque last night, and reports of youths damaging the building on Thursday.
More top news
Read Sadiq Khan's full victory speech, as the Tooting MP promised to be a mayor for "all Londoners".
Former footballer Frank Worthington has denied he is suffering from Alzheimer's - a day after his daughter said he was.
A list of results for London Mayor and the London Assembly