A campaign is underway to stop the English Defence League from coming to Tower Hamlets, amid fears of clashes between local residents and the far-right group.
Tommy Robinson, the controversial leader of the anti-Islamic group, unveiled plans to hold a protest in the area, which has a strong Muslim community, within weeks.
Mayor Lutfur Rahman is leading calls for Home Secretary Theresa May to ban EDL supporters from coming to the east London borough on 7 September.
Robinson spoke of his intention to return to Tower Hamlets when the terms of his bail expire, telling his 70,000 Twitter followers: "I can't wait till my bail conditions are gone so I can enter Tower Hamlets! I'm going straight to the East London Mosque #fact."
In response, Mayor Rahman fired off a letter to community groups and trade unions. He wrote that EDL protests "invariably result in violence against property, the police, or local communities.
"We have real fears that the EDL presence will act as a catalyst for further violence, disorder and destruction of property. There must be no place for hatred in our communities.
"The home secretary must act, and act now, to ensure the EDL is not able to bring its tour of hate to the streets of east London on September 7."
The East London mosque in Whitechapel was previously linked to fundamentalist Islamic preachers.
Left-wing groups clash frequently with the EDL at public events and tensions rose still higher after army soldier Lee Rigby was murdered by two suspected Muslim extemists in Woolwich, south London.