(QHA) - US lawmakers have warned that they may impose sanctions on Ukraine in response to violence against anti-government protesters in the European country. Assistant Secretary of State for European and Eurasian Affairs Victoria Nuland testified before the Senate Foreign Relations Committee on the situation in Ukraine, saying "all tools of government are on the table" including sanctions, AFP reported. On Sunday, at least 5,000 protesters rallied at Kiev’s Independence Square, known locally as the Maidan, to protest the beating of Ukraine’s leading opposition figure and former Interior Minister Yuriy Lutsenko a day earlier. Nuland denounced the attack on Lutsenko as well as "other acts of intimidation and criminality and efforts to stifle the media and political activity across the country." She called on Ukrainian President Victor Yanukovych to return to talks with the International Monetary Fund (IMF) to negotiate loans to help Ukraine's economy.