WASHINGTON - The first German official to tour the U.S. military-run prison in Guantanamo Bay, Cuba, said Wednesday that while the U.S. has improved conditions for inmates, his government still wants to see it closed.

After a tour of the prison this week, Germany's human rights commissioner Markus Loening praised the U.S. government for allowing his visit and answering most questions.

"It's great that the American government is more transparent about what is going on there," Loening said in an interview.

He noted, however, that he was not allowed to see the camp where high-value detainees are kept. Those 15 prisoners, including the self-proclaimed mastermind of the 9-11 attack, are held in a top-secret section known as Camp Seven.

Loening said Camp Seven wasn't even on the map he was shown of the Guantanamo facility during a presentation by the camp commander, Rear Adm. David B. Woods.

Loening said U.S. lawmakers bear responsibility for the failure to shut down the prison.

President Barack Obama pledged to close the prison within one year of taking office. But Congress has refused to allow the administration to move prisoners from the base to the United States.

Loening noted that the administration has reduced the number of inmates by sending some to their home countries or third countries. He said European countries have taken 51 detainees.

He urged lawmakers to reconsider their resistance to allowing the transfer of detainees to the United States, either to be tried in civilian courts or to live, if they are deemed innocent.

"If we can do it, you can do it," he said.

Loening said that the issue has symbolic resonance in the perception around the world of American values - and that it reflects on U.S. allies.

"I'm asked constantly when I am travelling around the world, whether I have talked to my American friends about this," he said. "There needs to be proof that even in a difficult situation like Guantanamo, American values are valid."