Washington's top diplomat for East Asian affairs has told Thailand's leaders that democracy must be restored in the country for relations to flourish between the longtime allies.

Assistant Secretary of State Daniel Russel met Wednesday with Prime Minister Prayuth Chan-ocha and other leaders in Thailand, where U.S. concerns about human rights under the military government have strained relations.

The two nations also discussed areas in which they can cooperate, including public health and combating human trafficking.

Both sides said after the meeting that they would try to strengthen ties that go back 182 years, but Russel stressed that Thailand would have to return to electoral democracy for their relationship to become fully productive.

Thailand's army seized power in a May 2014 coup. Elections are expected in 2017 at the earliest.