Tin Oo, the detained deputy leader of Aung San Suu Kyi's opposition party, was released on Saturday as the term of his house arrest expired.

The 82-year-old vice chairman of the National Leagues for Democracy (NLD) and former military commander-in-chief had been held under house arrest without trial for the past six years. He has been suffering from osteoporosis and has to wear a neck brace.

National League for Democracy (NLD) Vice Chairman Tin Oo speaks to reporters in his Rangoon residence, February 13, 2010. (Photo: Reuters)

He was arrested along with Suu Kyi in 2003 after a government-backed mob attacked their motorcade during a political tour in Upper Burma. He was initially held in prison in Kalay in northwestern Burma, but was brought back to Rangoon in February 2004 and placed under house arrest. His detention has been extended every year since then.

Activists and politicians in Burma said he was probably released because the regime believes his age and relative lack of popularity make him less of a threat to the upcoming polls than Suu Kyi.

“He is a good leader for the NLD, but he's not as influential as Aung San Suu Kyi, so the military  generals thought that he won't be able to obstruct the upcoming elections,” said Aye Thar Aung, an Arakan ethnic leader.

Often seen together with Suu Kyi during political tours, Tin Oo is reputed to be a reliable political colleague of the detained Nobel laureate. But some activists say the party leadership is unable to make bold decisions without Suu Kyi's release.

In 1976, Tin Oo was forced to retire from his position as commander-in-chief of the Burmese armed forces after he was accused of withholding information concerning a failed coup d'état against then dictator Gen Ne Win. He was tried on charges of committing high treason and sentenced to seven years with hard labor in 1977, but was released in a general amnesty in 1980.

He was later detained again, from 1989 to 1995, after becoming one of the founding members of the NLD in 1988. He has been denied access to visitors and fellow party leaders since his arrest in 2003.