The deputy chief of mission at Myanmar's embassy in Washington is seeking political asylum in the United States, Radio Free Asia reported on Sunday.
Career diplomat Kyaw Win, 59, had been posted in Washington since 2008 and defected because Myanmar's leaders were unwilling to relax their grip on power, the news agency said.
The U.S. Immigration and Customs Enforcement agency said it does not comment on asylum cases.
"Senior military officials are consolidating their grip on power and seeking to stamp out the voices of democracy," Win was quoted saying by Radio Free Asia. He said threats against opposition leader Aung San Suu Kyi "must be taken seriously."
Win, who served in four other capitals during his 31 years as a diplomat, is the second Myanmar deputy chief of mission to seek asylum in Washington. Former Major Aung Lynn Htut requested political asylum in March 2005, said Radio Free Asia, which broadcasts news in nine East Asian languages.