The two Balkan countries agreed to take the prisoners Tariq Mahmoud Ahmed al Sawah and Abd al-Aziz Abduh Abdallah Ali Al-Suwaydi on humanitarian grounds, the Pentagon said on Thursday.

The 58-year old Sawah was born in Egypt and has an Egyptian passport, but is also citizen of Bosnia and Herzegovina. Sawah allegedly admitted to working for al Qaeda. He reportedly developed explosive devices for the terror group, including magnetic limpet mines and a prototype shoe bomb.

According to the leaked prisoner files, Sawah turned out to be a "highly prolific source and has provided invaluable intelligence." The prisoner's health deteriorated during his 13 years of detention, with obesity and diabetes threatening his life.

US 'grateful' to Podgorica

Al-Suwaydi, a 41-year old Yemeni man, was captured in Pakistan in early 2002 and also spent more than 13 years in the controversial prison. His file states he was another al Qaeda member and explosives trainer.

"The United States is grateful to the government of Montenegro for its humanitarian gesture and willingness to support ongoing US efforts to close the Guantanamo Bay detention facility," the Pentagon said in a statement announcing Al-Suwaydi's release.

"The United States coordinated with the government of Montenegro to ensure this transfer took place consistent with appropriate security and humane treatment measure," the officials added.

Neither Sawah nor Al-Suwaydi were ever charged.

Obama racing against the clock

A third prisoner, Muhammad Bawazir, refused to accept resettlement. Attorney John Chandler said that the inmate insisted on being sent to one of the countries where his family members live.

The two latest transfers bring the prison population down to 91. The US officials has released 16 inmates from its military base prison since the start of the year.

US President Barack Obama vowed to close the facility before taking power in 2008, with many activists accusing the US authorities of committing human right's abuses.

The pressure is now mounting for Obama to fulfill his promise in face of political resistance, as he is set to leave office in one year.

On Thursday, the human right's watchdog Amnesty International urged the US president to immediately close the Guantanamo Bay prison. The activists accused the US of hypocrisy for urging other countries to uphold human rights while breaking them in Guantanamo.

"Guantanamo is a symbol of arbitrary use of state power in the name of war on terror," said Secretary General of Amnesty's German branch, Selmin Caliskan.

dj/kms (AP, AFP, Reuters, epd)