China then called on Wednesday for Myanmar's judicial sovereignty to be respected and warned international powers to stay out of the country's internal affairs.
Beijing has long adopted a policy of non-interference with Myanmar and has helped keep the impoverished nation economically afloat through trade ties, arms sales, and by shielding it from UN sanctions over rights abuses.
In return, China is assured of a stable neighbour and access to the country's natural resources.
The US-drafted text "condemns the conviction and sentencing of Aung San Suu Kyi and expresses grave concern about the political impact this action has on the situation in Myanmar".
It calls on the Myanmar government "to release Aung San Suu Kyi and all other political prisoners".
It also underlines the need for the military government "to establish the conditions and create an atmosphere conducive to an inclusive and credible political and electoral process with full participation by all political actors".
On Tuesday, a court in Yangon convicted Aung San Suu Kyi for breaching the terms of her house arrest, following an incident in which American John Yettaw swam uninvited to her home.
Yettaw, a Vietnam war veteran who suffers from epilepsy, was sentenced to seven years of hard labour and imprisonment.
Aung San Suu Kyi was given three years hard labour and imprisonment, but chief military ruler Than Shwe signed a special order commuting the sentence and ordering her to serve 18 months under house arrest.
The 64-year-old opposition leader, who has spent 14 of the last 20 years in jail or under house arrest, said the verdict was "totally unfair", according to Nyan Win, one of four lawyers allowed to visit Aung San Suu Kyi at her home on Wednesday to discuss an appeal.
"Daw Aung San Suu Kyi said the conviction was totally unfair and the court's assessment of the case was not just," Nyan Win, said, using an honorific for older women in Myanmar.
But she remained cheerful and alert, Nyan Win said, and seemed happy to be home after spending the last few months in Insein jail where her trial was held.