The military staged a coup in February 2021, detaining democratic leaders including Nobel laureate Aung San Suu Kyi, then violently suppressed protests, sparking a spiraling conflict.

The Treasury said in a statement it was imposing sanctions on Myanmar businessman Aung Moe Myint, the son of a military officer who it said facilitated arms purchases, as well as a company he founded, Dynasty International Company Limited, and two of its directors.

Aung Moe Myint, already under EU and British sanctions, used the company to facilitate the procurement of "various weapons, armaments, missiles, and aircraft," as well as aircraft parts, for Myanmar's military, the Treasury said.

The action freezes any U.S. assets of those designated and generally bars Americans from dealing with them.

"Today we are targeting the support networks and war profiteers that enable weapons procurement for Burma's military regime," Brian Nelson, Treasury's undersecretary for terrorism and financial intelligence, said in the statement, using the country's former name.

"Treasury will continue to take action to degrade the Burmese military's ability to commit brutal acts of violence against the people of Burma," Nelson said.

The State Department also barred former Myanmar police chief and deputy home affairs minister Than Hlaing from traveling to the United States for his involvement in human rights violations, the Treasury said, specifically citing the extrajudicial killings of peaceful protesters in February 2021.

The Myanmar Embassy in Washington did not immediately respond to a request for comment.

Western nations have issued numerous rounds of sanctions against the military and its businesses since the coup, but efforts to isolate the junta have failed to stop a slide into what a U.S. envoy called a civil war.

The sanctions, including those issued on Thursday, fall short of targeting Myanmar's gas sales, the military's largest source of foreign revenue, a move that anti-junta forces and human rights advocates say could influence the military's behavior.

"Current U.S. sanctions policy on Myanmar isn't working," said John Sifton, Asia advocacy director for Human Rights Watch. "This is like administering only half dosages of medicine and then hoping it will work like a full dose."

(Reporting by Simon Lewis, Susan Heavey and Daphne Psaledakis; Editing by Chizu Nomiyama, Bernadette Baum and Leslie Adler)

By Simon Lewis