The US attorney general said the UK gave "tremendous" cooperation - when asked if the US flew terror suspects through the UK without permission.
Suspected rendition flight in Prague, April 2005
British ministers say the current US Government has not asked to transport suspects through UK territory.
Alberto Gonzales refused to say whether the US had moved prisoners without explicit permission from the UK.
But he said the US did not fly suspects to nations where they might be tortured and fully respected UK sovereignty.
His comments came as the Ministry of Defence revealed where US planes suspected of secretly carrying suspects through Britain were flying to and from.
The Lib Dems threatened to complain to a watchdog if the ministry did not give the details about three planes which have featured in newspaper claims.
Among the planes' destinations and origins were Libya, Pakistan, Qatar, Malta, Morocco and the United States.
Lib Dems say UK ministers must ask the US more questions about the flights.
The party's foreign affairs spokesman Michael Moore said the UK should know how many suspects had been carried on such flights since 1998 and how many other detention centres are operated by the US or on its behalf.
He added: "What assurances can be given that the interrogation techniques used do not amount to 'cruel, inhuman or degrading' treatment, which is illegal under international law?"
US Secretary of State Condoleezza Rice has said suspects are flown abroad for interrogation - a process called rendition.
But UK Foreign Secretary Jack Straw has said there is no record of President George W Bush's administration asking for British airspace or territory to be used.
Giving the new details, Armed Forces Minister Adam Ingram said none of the information was at odds with Mr Straw's statements.
Mr Gonzales told BBC Radio 4's World at One on Tuesday that the US did not transport terrorism suspects to nations where it was more likely than not that they could be tortured.
Asked if the US might fly transport terror suspects through the UK without informing the government Mr Gonzales said "the United States respects the sovereignty of every European country including the UK".
Asked again, he added that the US had "a tremendous level of cooperation with the UK and with other European countries".
The Lib Dems say they want to know what kind of cooperation the UK gives, including what information the British security services gave the US.