The United States is suspending all engagement with Myanmar under a 2013 trade and investment agreement, as part of efforts to ramp up pressure on its military.
The Office of the US Trade Representative made the announcement on Monday, amid the ongoing military crackdown on citizens in Myanmar.
Protests continued in Yangon, Mandalay and elsewhere. Security forces responded by opening fire. Local human rights activists said the death toll from crackdowns since the coup rose to 459.
US Trade Representative Katherine Tai said in a statement that the US strongly condemns the security forces' "brutal violence against civilians."
Tai said the violence is a direct assault on the country's transition to democracy and efforts to achieve a peaceful and prosperous future.
The office said the suspension will remain in effect until the return of a democratically-elected government.
White House Press Secretary Jen Psaki told reporters that the US is deeply concerned by the recent escalation of violence against peaceful protesters.
She said Myanmar's security forces "are responsible for hundreds of deaths" in the country since the coup.
She also said the US condemns "this abhorrent violence" and continues to "make clear that we will impose costs on the military regime for the deadly violence."
The Trade and Investment Framework Agreement signed in 2013 was aimed at supporting economic reforms in Myanmar. It created a platform for dialogue and cooperation on trade and investment issues.
The administration of US President Joe Biden has already imposed economic sanctions on companies with deep links to Myanmar's military.