WASHINGTON (Reuters) - The United States is closely watching the situation in Saudi Arabia amid reported asset agreements between Saudi authorities and some detainees in an anti-corruption crackdown, U.S. Treasury Secretary Steven Mnuchin said on Friday. Asked about the agreements to hand over wealth for detainees  freedom, Mnuchin told CNBC  I think that the Crown Prince (Mohammed bin Salman) is doing a great job at transforming the country,  adding that the United States was  obviously monitoring the situation.  