Negotiations between embassy representatives and the US authorities in Washington started when the Chancellor Angela Merkel visited President George W. Bush last month, the German government source said.

Bernhard Docke, lawyer for the prisoner, Murat Kurnaz, 23, said Saturday he expected a result from the negotiations in the "near future."

According to an article to be published Monday in the German weekly Focus, Bush told Merkel he would free Kurnaz on condition that Germany give "guarantees of security," the details of which are now being discussed by German diplomats and government security experts. One of the conditions could be that German law enforcement authorities observe Kurnaz at all times.

Kurnaz, a Turkish national born in the north German city of Bremen, was arrested in 2002 by American forces in Pakistan, where he had moved in 2001. The German press nicknamed him "The Taliban of Bremen."

Transferred to the US prison camp in Guantanamo Bay under suspicion of terrorism, he complained to his lawyer a year ago of having undergone sexual humiliation by female soldiers at the detention center.

The German government hopes Kurnaz will be released by the summer, according to Focus.