Iran urged the European Union on Tuesday to resume talks on its nuclear dispute with the West, as world powers appeared split on how to handle the crisis, with Russia and China resisting calls for UN action. Russian Foreign Minister Sergei Lavrov said Tehran should first restore the basis for negotiations by halting the nuclear fuel research it resumed last week. "Talks presuppose an obligation. The Iranian obligation was to stick to the moratorium," Lavrov said. "Now Iran [has departed from] the moratorium on scientific research." He also sent a strong signal of Russia's opposition to sanctions and indicated it is not yet ready to refer Tehran's nuclear program to the UN Security Council. An Iranian source in Vienna said Iran had written to the EU trio proposing that talks restart immediately and saying Tehran was ready to "remove existing ambiguities regarding its peaceful nuclear program through talks and negotiations." However, a senior British official dismissed the offer, saying: "That is vacuous because the Iranians have created the conditions to make [further talks] impossible."