The State Department's top Asia diplomat says the Obama administration's outreach to Burma has produced only mixed results this far and that U.S. patience in awaiting reform moves is not unlimited. Assistant Secretary of State for Asian and Pacific Affairs Kurt Campbell says he expects more bilateral contacts soon.

Campbell's mission to Burma last November was the highest-level U.S. contact with the military government in 14 years.

While it yielded some initial conciliatory moves by Burmese authorities, Campbell said the U.S. outreach has yielded only a mixed bag of results thus far and that the United States will need to see some clear steps towards reform.

The Assistant Secretary's comments at a press event Tuesday were some of his most extensive to date on U.S. outreach to Burma, part of the Obama administrations broader efforts at dialogue with U.S. adversaries.

After the Campbell visit, the military authorities allowed detained Burmese democracy leader Aung San Suu Kyi to meet with some National League for Democracy Party colleagues.

But it has more recently said it will press ahead with a broadly-discredited plan for elections this year that would exclude much of the political opposition.

Campbell took note of what he said has been higher-level engagement between military authorities and Aung San Suu Kyi, whose party won elections in 1990 but was barred from taking office, and some other seemingly hopeful developments.

But the U.S. diplomat said there are areas of real concern concerning the treatment of Burmese minorities, political persecution and the detention since September of a Burmese-born U.S. citizen and democracy advocate.

Campbell said Secretary of State Hillary Clinton and her policy team are at this point looking for greater clarity on where the Burmese government is heading in the coming weeks.

"We went into this, both the review and the new set of policy priorities, with a very clear understanding of the challenges - that we had to be patient that that we had to recognize the enormous challenges that have come with every attempt, and strategy, for dealing with the regime," said Kurt Campbell. "But it is also the case that we're not unendingly patient. We will need to see some clear steps in due course."

Campbell said there had been some follow-on discussions with Burmese authorities since his November visit and that he expects another set of discussions in the near future, though he did not elaborate.

The State Department said three weeks ago, on the occasion of Burma's independence day, that the United States stands ready to take steps to improve relations, based on what it said should be reciprocal and meaningful efforts by the Burmese government to fulfill its peoples' democratic aspirations.