The United States is looking to see if Iran is prepared to engage seriously with the international community in the dragging talks on its suspect nuclear program, US officials said Monday. Iranian Foreign Minister Mohmmad Javad Zarif will attend key nuclear talks Thursday in New York, which \"will give our ministers a sense of their level of seriousnness and whether they are coming with concrete new proposals and whether this charm offensive actually has substance to it,\" a senior State Department official said.