Five terror suspects have been held pending deportation on the orders of the home secretary.
Charles Clarke says the five pose a threat to UK security
Charles Clarke says the presence of the five in the UK is not conducive to the public good.
The men, who have not been named, were detained in raids by the Immigration Service and police in the West Midlands, south Wales and London.
Ten men were detained under the same powers in August and another seven were detained in September.
A Home Office spokesman confirmed that early on Monday "the Immigration Service detained five 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".
"They will be held in secure prison service accommodation and we will not disclose their names," he added.
The Immigration Service detained the men after raids
A spokesman for South Wales Police said officers had supported the Immigration Service in a raid at an address in Cardiff at about 0600 BST which resulted in one man being held.
Monday's detentions bring to 22 the number who have been detained since July under the Immigration Act 1971 as part of a crackdown on terrorists and their supporters in the wake of the 7 July suicide bombings in London.
The Act gives powers to deport individuals and to detain them pending deportation.
At the end of August the home secretary defined the extended criteria under which foreigners considered to be promoting terrorism can be deported from the UK.
Mr Clarke issued a list of "unacceptable behaviour" by those said to indirectly threaten public order, national security, or the rule of law.
On 11 September, seven people - six in London and one in Manchester - were held under the Act.
Sources said all those detained on that date were Algerians and some were among the eight men cleared in April of involvement in an alleged ricin poison plot.
Ten men who were taken into custody on 11 August in the wake of the 7 July suicide bombings in London are appealing against their deportations.
The men, who include radical Jordanian cleric Abu Qatada, are seeking bail from the Special Immigration Appeals Commission in a hearing which began last Monday and will continue on Tuesday.
Britain is negotiating with various countries to ensure the detainees would not face torture or the death penalty if deported.
Under the Human Rights Act, the UK cannot deport anyone to a country where they may face persecution.
Last month, an agreement was made between the UK and Jordan that deportees would not be persecuted.
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