Iran on Saturday dismissed a U.S. decision to deny a visa to its proposed new envoy to the United Nations, saying it would take up the case directly with the United Nations. "We do **t have a replacement for Mr. Abutalebi and we will pursue the matter via legal mechanisms anticipated in the United Nations," Abbas Araghchi, a senior Foreign Ministry official and top nuclear negotiator, was quoted by Iran's official IRNA news agency as saying. The United States said on Friday it would **t grant a visa to Hamid Abutalebi, citing the envoy's links to the 1979-1981 hostage crisis.