KIEV, Ukraine (AP) — Ukrainian opposition leaders issued a stark ultimatum to President Viktor Yanukovych on Wednesday to call early elections within 24 hours or face more popular rage, after at least two protesters were killed in confrontations with police in a grim escalation of a two-monthlong political crisis.

The protesters’ deaths, the first since the largely peaceful protests started in November, fueled fears that the daily demonstrations aimed at bringing down the government over its decision to shun the European Union for closer ties to Moscow and over human rights violations could turn more violent.