Ten Yemeni men, held for more than a decade at the controversial US military prison at Guantanamo Bay, were transferred to the Gulf Arab nation of Oman on Thursday.

The transfer brings the total number of prisoners at the detention center to 93. This is the first time it has fallen below 100 since the detention center was opened in 2002 under former US President George W. Bush.

"After a deliberate and careful review, we completed the transfer of 10 Yemenis - roughly 10 percent of the total remaining [Guantanamo] population - to the government of Oman," said US Defense Secretary Ashton Carter during a speech at the US military's Southern Command.

"Like every transfer that came before it, the decision to transfer these detainees happened only after a thorough review by me and other senior security officials of the government," Carter added.

The Yemeni men transferred to Oman on Thursday were all held for more than a decade without charge or trial.

The Omani foreign minister said his country received the men "in response to a request by the US administration for help to resolve the issue of detainees at Guantanamo Bay," according to a statement broadcast by the country's state news agency.

In his final State of the Union address, US President Barack Obama on Tuesday urged the Republican-led Congress to aid the process of closing the controversial prison, which gained notoriety for holding "enemy combatants" without trial and using draconian torture techniques on detainees.

"It's expensive, it's unnecessary, and it only serves as a recruitment brochure for our enemies," Obama said, referring to the prison.

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ls/jil (Reuters, AFP, AP)