CARACAS - Venezuelan socialist President Nicolas Maduro said on Friday the United Nations human rights chief was a puppet of the United States who had implanted himself like a "tumor" and had no right to criticize Maduro's handling of the crisis-stricken nation.U.N. High Commissioner for Human Rights Zeid Ra’ad Al Hussein said on Wednesday that crimes against humanity may have been committed by state forces in Venezuela and voiced alarm at “the erosion of democratic institutions” in the country.Maduro, who says there is a right-wing plot to sabotage his government, deflected the criticism during brief comments to journalists broadcast on state television."The high commissioner is a militant of the fascist Venezuelan right. ... He is a pawn of the State Department who is embedded like a tumor in the human rights system," Maduro said. "He is a person who has lost all credibility to opine about our country."Opposition politicians say an increasingly isolated Maduro is picking fights with foreign critics instead of trying to fix a brutal economic meltdown in the oil-rich country. Venezuelans are suffering a fifth year of a recession that has sparked disease, malnutrition, hyperinflation and mass emigration.The main opposition coalition is boycotting a May presidential election, saying it is a farce intended to legitimize Maduro's “dictatorship.”Zeid also criticized the vote this week, saying that the context “does not in any way fulfill minimal conditions for free and credible elections."