The US Treasury placed Myanmar state-owned timber and pearl businesses on its sanctions blacklist on April 21, saying they were used to generate revenue for the military regime.
The treasury placed sanctions on Myanma Timber Enterprise and Myanmar Pearl Enterprise, which are responsible for timber and pearl exports from the former Burma.
The sanctions aim to restrict the companies' access to the global trading and financial system by forbidding US individuals and companies, including banks with US arms, from doing business with them.
The sanctions also freeze any property held by the two companies under US jurisdiction.
The sanctions came as Washington seeks to add pressure on the country's military after it ousted civilian leader Aung San Suu Kyi and seized power in a February 1 coup.
Since then protests have swept the country, and at least 738 people have been killed and 3,300 are languishing in jails as political prisoners, according to a local monitoring group.
"Our action today reinforces our message to the military that the United States will continue to target specific funding channels and promote accountability for the coup and related violence," said Secretary of State Antony Blinken.
"We will continue to support the people of Burma in their efforts to reject this coup, and we call on the military regime to cease violence, release all those unjustly detained, and restore Burma's path to democracy," he said.