The seven were held early this morning in an operation supported by officers from the Metropolitan Police and Greater Manchester Police. They were transferred to secure prison service accommodation.
A Home Office spokesman said: "We can confirm that early today the Immigration Service detained seven individuals in accordance with the Home Secretary's powers to deport individuals whose presence in the UK is not conducive to the public good for reasons of national security.
"The Immigration Act 1971 grants powers to deport individuals and detain them pending deportation. The Immigration Service has detained the seven foreign nationals on this basis. They will be held in secure prison service accommodation and we will not disclose their names."
The Home Office spokesman would not say where the men were being held.
A Scotland Yard spokesman said: "We can confirm that officers from the Metropolitan Police Service (MPS) have this morning at approximately 6am supported the immigration service as they served notice under the Immigration Act at a number of addresses across the capital.
"A number of individuals were detained by the immigration service. Police assisted with the transfer of these individuals into the care of the prison service. MPS officers have made no arrests and have not taken any individuals into police custody."
A police spokesman added: "We can confirm that officers from Greater Manchester Police (GMP) this morning supported the Immigration Service in an ongoing operation in the Manchester area.
"The GMP operation was to allow the Immigration Service to safely carry out a Home Office deportation order on one man who has now been detained."
In August, 10 terrorism suspects including a radical preacher described as "al-Qa'ida's ambassador to Europe" were detained in a series of similar swoops.
The radical preacher Abu Qatada - described by a British court as "a truly dangerous individual" - was among those seized in the raids.
The Home Secretary invoked the same powers used today, which allow him to seek to remove those considered a threat to national security.
In an unprecedented arrangement completed before the August arrests, ministers finalised agreements to allow the 10 to be deported to countries including those with poor human rights records.Reuse content