Soldiers stand guard on a blockaded road to Myanmar's parliament in Naypyidaw on February 1, 2021.

The United States on Thursday imposed sanctions on a Myanmar businessman and two others involved in procuring Russian-made weapons from Belarus for the junta that seized power in the Southeast Asian country early last year, Secretary of State Antony Blinken said.

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 US 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 deals including for missiles and aircraft, as well as a company he founded, Dynasty International Company Limited, and two of its directors.

Reuters was unable to reach Aung Moe Myint for comment.

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

Blinken in a statement cited Myanmar’s execution of four activists in July and a deadly attack on a school by a military helicopter last month. He also pointed to a role the three people sanctioned on Thursday allegedly played in obtaining Russian-produced arms from Belarus.

“These designations also implicate the Burmese military’s long-time ties to the Russian and Belarusian militaries,” Blinken said, using the country’s former name.

“We will continue to use our sanctions authorities to target those in Burma and elsewhere supporting Russia’s unlawful invasion of Ukraine, as well as Russia and Belarus’ facilitation of the Burmese regime’s violence against its own people.”

Russia is a main source of military hardware for the Myanmar military and has provided diplomatic cover amid international condemnation of the coup. Junta leader Min Aung Hlaing visited Russia twice in recent months.

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 US 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.”