"We are appalled and revulsed to see the horrific violence perpetrated against the people of Burma for their peaceful calls to restore civilian governance," State Department spokesman Ned Price said, using Myanmar's former name.

"We call on all countries to speak with one voice to condemn the brutal violence by the Burmese military against its own people," he told reporters.

He said the United States, which has imposed sanctions on junta leaders, was looking at further actions.

He also called for more effort from China, a frequent US adversary that Myanmar's military has historically considered its main ally.

"China does have influence in the region. It does have influence with the military junta. We have called upon the Chinese to use that influence in a constructive way in a way that advances the interests of the people of Burma," Price said.