Four Afghans held for more than a decade at Guantanamo Bay have been sent home, the Pentagon said Saturday, edging President Barack Obama closer toward his goal of closing the controversial US military jail.

The Department of Defense said the men -- Shawali Khan, Khi Ali Gul, Abdul Ghani and Mohammed Zahir -- had been moved from the prison after a comprehensive review of their case.

"As a result of that review, which examined a number of factors, including security issues, these men were unanimously approved for transfer by the six departments and agencies comprising the task force," a Pentagon statement said.

The releases come hard on the heels of the transfer of six Guantanamo detainees to start new lives in Uruguay earlier this month.

Obama has vowed to close the jail in Cuba, set up to house terror suspects following the September 11, 2001 attacks.

"This repatriation reflects the Defense Department's continued commitment to closing the detention facility at Guantanamo in a responsible manner," said Paul Lewis, the Pentagon's envoy for the closure of Guantanamo.

The latest transfers leave 132 detainees at Guantanamo Bay, the Pentagon said.

The four men, in their 40s or early 50s, were arrested in Afghanistan between 2002 and 2003. They were initially alleged to have had strong ties to the Taliban or Al-Qaeda.

- 'Terrible treatment' -

However, lawyers have long argued that the evidence against the men is threadbare.

An attorney for Ghani, detained in Kandahar in December 2002, said Saturday his client was a "simple man" sold to US forces for a bounty.

"Ghani should never have been imprisoned in the first place, let alone for more than a decade," said lawyer Barry Wingard, a retired US Air Force lieutenant colonel.

"After many years of terrible treatment at the hands of his captors, Abdul returns to his homeland as innocent as the day he was taken from his family."

Lawyers for Khan, who was handed over to US forces by Afghan warlords in November 2002, complained he had been held on the basis of uncorroborated evidence of a single informant.

"Shawali was sent to Guantanamo on the flimsiest of allegations that were implausible on their face and never properly investigated, and held for 11 years without charge," said Baher Azmy, legal director for the Center for Constitutional Rights.

- Family reunions -

In Kabul, Afghanistan's High Peace Council, the government-created body set up to strengthen relations with insurgents, welcomed the release.

All four men would be reunited with their families in the "near future," the council said, calling for remaining Afghans held at Guantanamo to be released.

A US State Department statement said the release would help forge closer ties with Afghanistan.

"The United States hopes that this transfer is a step forward in strengthening relations between the two countries and can provide an opportunity for greater confidence among Afghans to engage in political dialogue to end the violence in their country," the statement said.

Obama came to power six years ago promising to close Guantanamo but has been frustrated in his efforts by a combination of opposition from Congress and the difficulties involved in finding homes for prisoners who are often unwanted by their home states and/or suspected of involvement in terrorism.

Of the 132 detainees left at Guantanamo, 63 have been cleared for release by the US administration.

About 15 of the men who have not been cleared for release are classified as "high value" detainees.

US law currently bars any transfer of a Guantanamo detainee to the United States for trial or incarceration.

For Guantanamo to be closed, Obama will have to persuade Congress to accept the transfer of this group to US facilities, an unlikely scenario.