Human Rights Watch on Friday condemned the decision by Myanmar's military rulers to extend the house arrest of democracy activist Tin Oo, the top deputy to Nobel peace laureate Aung San Suu Kyi.
The military government in the country formerly known as Burma extended Tin Oo's detention by another year on Tuesday.
He and Aung San Suu Kyi have both been detained since May 2003, when their convoy was ambushed by a pro-government mob during a political tour of northern Myanmar.
The New York-based watchdog accused Myanmar of using diplomatic cover from China and Russia to further its repression of the democracy movement, after Beijing and Moscow last month vetoed a UN resolution demanding reforms from the junta.
"The Burmese government relies on China and Russia's backing to flout the international community's demands to free political prisoners like Tin Oo," said Brad Adams, Asia director at Human Rights Watch.
"The continued detention of the leaders of the party that won the last election in Burma shows how the military junta is fearful of political dissidents striving for democracy."
The National League for Democracy (NLD), headed by Aung San Suu Kyi, won 1990 elections in a landslide but has never been allowed to govern.
The United States had proposed a UN Security Council resolution to pressure the regime to follow through on promises to reform and to release political prisoners including Aung San Suu Kyi and Tin Oo.
But the resolution was defeated by a rare double veto from Russia and China, who have been expanding their ties with the Southeast Asian nation.