By Andrea Shalal WASHINGTON, July 10 (Reuters) - The United States on Friday issued new Iran-related sanctions targeting a key financier for Iran's new leader Mojtaba Khamenei and 13 other individuals and entities, following Tehran's resumed attacks on oil tankers in the Strait of Hormuz, the Treasury Department said. The sanctions took aim at Ali Ansari, an Iranian banker and businessman based in Dubai who had previously been sanctioned by Britain for his role in financially supporting the act