Police arrested 13 women at the Omega massage parlour

Police originally arrested 11 men and 47 women on Friday night in co-ordinated raids on ten locations including two massage parlours.

Nine of the men were released on bail a day later.

A further man, arrested at his home in Sheffield on Saturday afternoon, was released on bail on Sunday.

Organised criminals are relentless in their exploitation of vulnerable people to make money David Blunkett Home Secretary

The raids, codenamed Rampart, were part of government efforts to tackle organised immigration crime.

More than 300 police and immigration officers took part in the operation.

At 2030 BST on Friday, police raided two premises in Leeds and Sheffield described as "massage and sauna parlours".

Assistant Chief Constable for South Yorkshire, Ian Daines, said: "In the parlours a number of young woman were detained who are now being interviewed by the immigration service."

Home Secretary David Blunkett said the government was determined to crack down on gangmasters who bring immigrants into the UK to work illegally.

"Organised criminals are relentless in their exploitation of vulnerable people to make money.

'Immoral earnings'

"This operation shows the determination of the police and other agencies to put these people out of business and behind bars."

Officers targeted Winston's on Dewsbury Road, Leeds and Omega, Attercliffe Road, Sheffield.

At the same time, officers entered one property in Rotherham and six in Sheffield which has resulted in a number of alleged illegal immigrants being detained for questioning.

We wouldn't say this is a one-off - there are a number of investigations across the whole of the region ACC Ian Daines

ACC Ian Daines said: "We believe the immigrants are from European countries, and they are all adults, generally young women."

At the Omega parlour 13 women were detained for immigration offences, while another 34 were held at Winston's.

The police stressed that the women were being treated as "victims" but were still being held in order to establish their immigration status.

Eleven men were detained after Friday night's raids on suspicion of living off immoral earnings and being involved in the people smuggling trade.

A spokeswoman for South Yorkshire Police said all the men questioned in connection with the raids were from the Sheffield and Rotherham areas.

Nine of these men were released on police bail on Saturday evening pending further inquiries.

The twelfth man, who was arrested at his home in Sheffield on Saturday afternoon by Operation Rampart officers, was also released on bail on Sunday.

A spokeswoman for South Yorkshire Police said on Sunday that another man and woman from the Sheffield area had also been quizzed in connection with the operation.

But the pair had not been arrested and had volunteered to help police.

Parlours 'closed'

A total of 100 officers from South Yorkshire and 150 from West Yorkshire were involved in the operation, which was co-ordinated between the two forces and the UK Immigration Service.

ACC Ian Daines said: "We have been developing information about the premises over recent months and it may take some time to analysis the evidence.

"We wouldn't say this is a one-off. There are a number of investigations across the whole of the region."

He added that members of the public can help the police crack-down on immigration.

He said: "We would encourage people with suspicions about anyone exploiting illegal immigrants to contact Crimestoppers."