The U.S. Treasury has blacklisted a hard-line lawmaker of Myanmar's ruling party, accusing him of undermining political and economic reforms.
Aung Thaung (Awn(g) Tong) was industry minister under the former ruling junta and his family has extensive business interests in Myanmar.
Friday's statement from Treasury said that by undermining the transition in Myanmar, Aung Thaung was "perpetuating violence, oppression, and corruption." The action prohibits Americans from doing business with him.
The announcement comes two weeks ahead of a visit to Myanmar by President Barack Obama.
Aung Thaung was a leader of a pro-military organization accused of conducting a 2003 attack on a convoy carrying opposition leader Aung San Suu Kyi (Awn(g) San Soo Chee).
He has denied allegations that he has been behind recent mob violence against minority Muslims.