By Jon Smith, PA Political Editor
US Attorney General Alberto Gonzales today sought to reassure British critics of Guantanamo Bay and so-called rendition flights through European airspace.
Mr Gonzales said British officials understood that when someone was ''captured on the battlefield something has to be done with them''.
He insisted America was constantly re-assessing whether the detention camp at Guantanamo Bay - which Prime Minister Tony Blair has called ''an anomaly'' - was effective and lawful.
He also said the US respected the sovereignty of every European country when asked directly if rendition flights had moved through UK airspace or UK airports without the Government's permission.
The British Government has said there have been no requests for such flights since September 11, 2001.
Mr Gonzales, on a visit to London, told BBC Radio 4's The World at One: ''We are aware of concerns here in Europe about activities in Guantanamo. Part of the reason for my visit is to provide re-assurance about what the US is in fact doing.
''One of the things we are constantly doing is re-assessing all of our activities in the war against terrorism and doing those things that remain effective and remain lawful.
''British officials understand that when someone is captured on the battlefield something has to be done with them.
''You can't simply release them. You can't shoot them. You have to do something with them.''
Mr Gonzales said it was lawful to detain them ''for the duration of hostilities''.
He added: ''This is something we need to do to protect the United States.''
His message to critics was: ''We hear what you are saying, we are aware of your concerns, we are here to communicate exactly what's going on in Guantanamo.
''If there are alternatives, we are always willing to look at that.''
Asked if the US would always seek the permission of a government before flying suspects through their airspace on ''rendition'' flights to a third country, Mr Gonzales said: ''The US government respects the sovereignty of every European country, including the UK.
''We do not render individuals where we believe it's more likely than not that they will be tortured.''
Mr Gonzales went on: ''We have a tremendous level of co-operation with the UK and other European countries and we very much respect the sovereignty of every country.''
Mr Blair has said Britain has an agreement with the US that rendition flights would not take place through its airspace without a formal request.
Amnesty International UK director Kate Allen said: ''Mr Gonzales' comments on rendition do little to allay our fears that UK airspace may has been used to allow known rendition aircraft to land, refuel and take off from British runways.
''The fear then is that people are being flown to places where their human rights will be severely curtailed and they may be subjected to torture.
''Why fly people to countries like Jordan or Egypt in the first place? Could they not be questioned in the US or indeed in the country where they were first apprehended?
''The UK Government must allow a full independent investigation into any UK complicity with rendition flights.''
