The U.S. State Department's top diplomat for Asia said Thursday the Obama administration is quite dissatisfied with results of its effort to prod Burma's military government toward reform. Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell last week completed his second visit to Burma since late last year.

Campbell, who has headed the U.S. effort at outreach with Burma, gave no indication that the administration is giving up on the dialogue. But he is making clear that Burmese authorities have not been responsive to U.S. reform appeals.

In his first comments on the subject here since returning from Burma May 10th, Campbell said the United States has so far been rebuffed on its appeals to Burmese authorities to open up national dialogue in advance of promised elections later this year.

He also reported no movement on calls on Burma to release political prisoners, ease tensions with minority groups, and cooperate with the U.N.-mandated embargo on North Korea because of its nuclear program.

"On each of these issues, we are troubled by developments, and we are calling on the government to follow through on specific steps to allow not only a better relationship with the United States and the international community, but a better future for its people overall," said Kurt Campbell.

Campbell, on his second mission to Burma since last November, met with military authorities and was allowed to meet with opposition and ethnic group leaders including detained democracy leader Aung San Suu Kyi.

Controversial rules for elections promised later this year exclude Aung San Suu Kyi. Her National League for Democracy Party (NLD), which won the country's last elections in 1990, decided to disband rather than accept vote restrictions.

However some NLD members decided to form a new party that will stand in the elections.

Campbell said as he left Burma last week that he respects the difficult decisions of both those taking part and opting out of the electoral process, and said the United States will continue to press for reform.

He said it is simply tragic that authorities had  rebuffed the countless appeals from Aung San Suu Kyi, detained most of the time since 1990, to work together for a better future for the country.

Burma is expected to be among issues on the agenda for Secretary of State Hillary Clinton, who begins a trip to Japan, China and South Korea Thursday.