WASHINGTON (Reuters) - The United States has concluded its first set of human rights talks with Myanmar and is confident it now has an "open channel" to discuss political prisoners and other sensitive subjects as ties improve, the State Department said on Wednesday.

Michael Posner, the State Department's top human rights official, led the U.S. team at the talks in Myanmar's capital Naypyitaw, which come as the Obama administration dismantles longstanding sanctions to reward Myanmar's leaders for political and economic reforms.

"The results of the dialogue were assessed to be very positive and we look forward to continuing these discussions with Burmese authorities," State Department spokeswoman Victoria Nuland told a news briefing.

"We weren't sure whether the Burmese would be open to addressing all of those issues, and they were," Nuland said.

"We are confident that we have now an open channel with the government of Burma to discuss human rights and to continue to work on bringing them where they want to be in terms of human rights standards for their government."

The United States has seen ties warm rapidly with Myanmar since a quasi-civilian government took office in March 2011, ending five decades of military rule and launching rapid reforms including overhauling the economy, easing censorship, legalizing trade unions and protests and freeing political prisoners.

The United States has responded with diplomatic and economic gestures, sending Secretary of State Hillary Clinton to Myanmar last year and easing sanctions.

Myanmar released its latest group of political prisoners last month, just before Myanmar President Thein Sein and veteran pro-democracy leader Aung San Suu Kyi visited the United States on separate trips.

"We have all spoken out about the need to get to zero in terms of political prisoners and we're continuing to work with the government of Burma on that," Nuland said.

The United States has also expressed concern over ongoing fighting with ethnic minority rebel groups and violence against ethnic Rohingya Muslims in western Rakhine state, as well as the government's continued military ties with North Korea.

(Reporting by Andrew Quinn; Editing by Jackie Frank)