Suu Kyi, a Nobel peace prize laureate, was arrested on May 30, with dozens of her supporters, after pro-government forces attacked her convoy on a provincial tour. Several opposition members were killed and the incident sparked international condemnation of the regime.
Washington called on the authorities to release Suu Kyi and the imprisoned supporters of her National League for Democracy.
"The Burmese authorities have full responsibility for her health, having placed her in so-called protective custody since [the] premeditated attack on her convoy. They are also fully responsible for the welfare of all political prisoners," the US state department said.