Iran and the United States have differing views over the scope and mechanism to lift sanctions on Tehran in exchange for curbs on its nuclear programme, a senior Iranian official told Reuters on Sunday, adding that new talks were planned in early March. The official said Tehran could seriously consider a combination of exporting part of its highly enriched uranium (HEU) stockpile, diluting the purity of its HEU and a regional consortium for enriching uranium, but in return Iran's right to "