(QHA) - Top Western diplomats headed to Kiev Tuesday to try to defuse a stand-off between President Viktor Yanukovych's government and thousands of demonstrators, following a night in which police in riot gear dismantled protesters' encampments outside government buildings, reports AP. EU foreign policy chief Catherine Ashton and U.S. Assistant Secretary of State Victoria Nuland are expected in Kiev Tuesday, set to meet with Yanukovych and the opposition. As Ukrinform reports, Ashton has expressed concern about military intervention and the searches conducted in the Kyiv office of the Batkivschyna Party. Ashton said this in a statement released on the eve of her visit to Ukraine on Tuesday, Ukrinform reported. "On the eve of my visit to Kyiv, I follow with concern the reports that police forces forcibly entered the office of the biggest opposition party, Batkivshchyna," Ashton said. The protests, in their third week, started after Yanukovych backed away from signing an agreement on deepening ties with the European Union, a pact that many Ukrainians desired in order to tilt West and lessen Russia's influence on the former Soviet republic.