In his first visit to Egypt, the US attorney-general has defended the secret transfer of terrorism suspects to countries where they could face torture - a practice the US calls "extraordinary rendition".
But Alberto Gonzales refused to confirm reports that Egypt, with a human rights record the US has criticised, was one of those countries.
"I'm not going to confirm that there have been any [suspects sent to Egypt], and I'm certainly not going to talk about the numbers - it's intelligence activity and we just don't do that," Gonzales told reporters after meeting Hosni Mubarak, the Egyptian president.
"All I can say is that we do have an obligation to seek assurances from any country in which we are returning someone, that the individual is not going to be tortured," he said.
Gonzales said the US would send a justice department lawyer to be stationed in Cairo "so we can further cement our relationship and we have someone on the ground representing me".
The United States has said it does not condone torture or send anyone to countries that practise torture, but human rights groups have raised concerns about the rendition of terrorism suspects.
Habib el-Adly, the Egyptian interior minister, has denied Egypt was receiving or torturing suspects from abroad.
"I'm not going to confirm that there have been any [suspects sent to Egypt], and I'm certainly not going to talk about the numbers"
Detainees have said they were transferred from the US to alleged secret facilities in countries including Poland, Romania, Jordan and Egypt - where some said they were mistreated or tortured.
Gonzales refused to confirm the existence of such facilities, although he acknowledged the practice of sending terrorism suspects to prisons in their home countries.
He said he saw no contradiction between the US running a facility such as Guantanamo, where activists and former detainees have alleged abuse, and promoting democracy around the world.
"We have procedures in place to ensure that those at Guantanamo in fact deserve to be at Guantanamo," Gonzales said.
"We're looking for ways to deal with terrorists other than at Guantanamo if we can - the US has no intention and no desire to be the world's jailers."