The highest-level US officials to visit Myanmar in 14 years held talks Wednesday with the military-ruled country's prime minister, Thein Sein, a Myanmar official said.

Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell and his deputy Scot Marciel met Thein Sein in the administrative capital Naypyidaw on the second and final day of their trip.

"They are meeting now," a Myanmar official said on condition of anonymity.

The US duo were due to meet pro-democracy leader Aung San Suu Kyi later Wednesday in the former capital, Yangon.