J. Scott Applewhite/AP Photo

"The United States expresses its disgust with the decision of Ukrainian authorities to meet the peaceful protest in Kyiv's Maidan Square with riot police, bulldozers, and batons, rather than with respect for democratic rights and human dignity. This response is neither acceptable nor does it befit a democracy," Kerry said in a statement late Tuesday.

Ukrainian police have reportedly clashed with demonstrators and opposition lawmakers in Kiev's Independence Square, removing barricades and attempting to break up the protests, which have raged since President Viktor Yanukovych's decision not to sign a trade deal with the European Union.

"As church bells ring tonight amidst the smoke in the streets of Kyiv, the United States stands with the people of Ukraine," Kerry said. "They deserve better."

Assistant Secretary of State Victoria Nuland was in Kiev Tuesday along with EU High Representative Catherine Ashton after traveling to Moscow the previous day for emergency meetings with Russian diplomats.