DCI Adam Lowe said:
"These arrests are part of an investigation into rape and serious sexual assault carried out by a group of men in Newham and the wider east London area. Our enquiries continue.
"I would urge anyone who has been a victim of this type of offence or who believes they have any information to please contact police on 020 8217 6531, or Crimestoppers on 0800 555 111."
More top news
An English springer spaniel given to the UK Border Force has become a star new recruit for sniffing out smuggled cash.
Celine Dookhran, 20, was allegedly kidnapped by her relative Mujahid Arshid, 33, and his employee Vincent Tappu, 28, on July 19 last year.
Collins hid the device, two sim cards and two memory sticks inside a crutch while on remand in September.