HAVANA - Russian Foreign Minister Sergei Lavrov slammed the United States and European Union on Tuesday for imposing sanctions on Russia over the Ukraine crisis, saying they were the work of weak politicians in the West "attempting to blame others."The European Union on Tuesday announced asset freezes and travel bans on 15 Russians and Ukrainians over Moscow's actions in Ukraine, one day after the United States imposed sanctions on seven Russians and 17 companies linked to Russian President Vladimir Putin."We reject sanctions in any of our relationships, in particular those sanctions that were sponsored by the United States and the European Union, which defy all common sense, regarding the events in Ukraine," Lavrov said during a visit to Cuba."The attempts to blame others is the result of weak politicians or rather of those politicians who understand that their geopolitical ambitions have failed, and they are attempting to blame others," Lavrov said.Russia annexed the Crimea region after Ukraine's pro-Moscow president was ousted in February by protesters demanding closer links with Europe. Kiev and the West accuse Russia of stirring up a separatist campaign in the east of Ukraine, a charge Moscow denies.Cuban Foreign Minister Bruno Rodriguez and Nicaragua's President Daniel Ortega, who Lavrov met in Managua later on Tuesday, both voiced support for Russia's opposition to sanctions."The path forward isn't one of sanctions or pressures, the path forward is one of dialogue that respects international law," said Ortega, a long-time antagonist of the United States.Lavrov is on a long-scheduled trip to Latin America this week.