Police and immigration officials have arrested 13 women and two men in a crackdown on suspected organised crime.
The Met said there would be more raids in the future
The Metropolitan Police and the Immigration Service have been working together to target criminals from eastern Europe, whom they suspect control prostitution in London and other British cities.
Police said on Friday morning more than 30 addresses across London had been raided in the last 24 hours.
The raids were on premises in Kilburn, Paddington, Harrow, Cricklewood, Tooting, Wembley and Islington, among others.
False papers, including passports and identity documents, were seized.
One address in South Kensington revealed 17 false British and European passports, police said.
Police said those arrested were thought to have been involved in the illegal sex industry.
Some were thought to have links to organised crime, and most were in the country illegally.
These crime groups are also involved in whole range of other illegal activity including kidnapping, identity theft, drugs trafficking, and money laundering
Assistant Commissioner Tarique Ghaffur
Seven of the women arrested were from Thailand, and a number of others were from Eastern Europe, police said.
The new arrests followed the arrests of two women on Thursday, in connection with identity fraud.
Assistant Commissioner Tarique Ghaffur said: "We have focused on the illegal sex industry because we know that it is being infiltrated by organised crime groups - particularly those from Eastern Europe.
"But these crime groups are also involved in whole range of other illegal activity including kidnapping, identity theft, drugs trafficking, and money laundering.
"This is the start of a concerted effort to take out these criminals, and generally make it very difficult for them to operate in London."
The arrests and raids were carried out under Operation Maxim.
This falls under the umbrella of Reflex, the government's task force which deals with organised immigration crime.
The police will use a mobile screening system to take fingerprints of suspects which can be checked within seconds on databases throughout Europe.
BBC crime correspondent Neil Bennett said the scheme would help cut through the false documentation and bogus identities associated with this type of crime.
With Home Office approval, the police will also support applications to remain in the UK from women who are prepared to be witnesses against their former pimps.