x     The US government is weighing a federal indictment against former Cuban president Raúl Castro over the 1996 downing of two civilian aircraft operated by the humanitarian organization Brothers to the Rescue, the CBS network and the Reuters news agency reported on Thursday, citing official sources. The potential charges, which still require grand jury approval, emerge on a day marked by escalating tensions between Washington and Havana and by a confidential visit to the Cuban capital by CIA