The United States is not standing in the way of foreign banks doing business with Iran, a senior U.S. official said, but his comments appeared unlikely to satisfy frustrated businessmen and Iranian officials. Most international sanctions against Iran's economy were lifted in January after Tehran implemented a deal with world powers to curb its nuclear programme. But Washington kept some sanctions that were originally imposed over missile proliferation and alleged support of terrorism. The fear of being caught up in those remaining sanctions has deterred most foreign banks from restoring links with Iran, angering the Iranian government.