By Aung Hla Tun
YANGON (Reuters) - Myanmar's leaders must pursue "genuine" reforms that involve Nobel laureate Aung San Suu Kyi and make progress in freeing thousands of political prisoners before ties can improve with Washington, a U.S. envoy said on Wednesday.
But the new U.S. special representative to Myanmar, Derek Mitchell, declined to identify specific conditions for lifting sanctions in place since the military crushed a 1988 student uprising.
"I consider this a highly productive visit," Mitchell told reporters at Yangon's main airport at the end of a six-day trip to the army-dominated, reclusive former British colony also known as Burma.
He met a range of officials in the capital Naypyitaw, including cabinet members of the nearly year-old parliament and with opposition politicians led by Suu Kyi, but he did not meet President Thein Sein.
Mitchell said he asked officials to free about 2,000 political prisoners, maintain dialogue with the opposition and investigate human-rights abuses. He also raised concerns about Myanmar's military relationship with North Korea.
"Progress on these issues will be essential to progress in the bilateral relationship," he said. "If the government takes genuine and concrete action, the United States will respond in kind."
Recent rare overtures by Myanmar's authoritarian rulers toward liberalization have stirred speculation of possible reforms in the resource-rich country, which has been blighted by 48 years of oppressive military rule and starved of capital.
Last month, President Thein Sein held an official meeting with Suu Kyi, who was detained for 15 years until freed from house arrest last November.
"Any credible reform effort must include her participation," said Mitchell.
Most experts doubt sanctions will be lifted until political prisoners are freed. Mitchell said he held a "candid" dialogue and "very productive exchange" with Myanmar officials on the issue of political prisoners but received no commitment.
"I noted that many within the international community remain skeptical about the government's commitment to genuine reform and reconciliation, and I urged authorities to prove the skeptics wrong," he said.
(Writing by Jason Szep; Editing by Robert Birsel)