Oba­ma be­gan his three-coun­try, five-day tour of Latin Amer­i­ca against the back­drop of omi­nous de­vel­op­ments in earth­quake-rav­aged Japan, where of­fi­cials strug­gle to pre­vent a melt­down at a dam­aged nu­clear pow­er plant, and in Libya, where a US and Eu­ro­pean coali­tion launched a risky mil­i­tary op­er­a­tion to pro­tect civil­ians from at­tacks by Gad­hafi's force. The White House said Oba­ma was briefed on de­vel­op­ments in Libya ear­ly Sat­ur­day by Sec­re­tary of State Hillary Clin­ton and na­tion­al se­cu­ri­ty ad­vis­er Tom Donilon. Brazil stands out for its strate­gic and eco­nom­ic im­por­tance to the Unit­ed States. As the world's sev­enth-largest econ­o­my, it is a mem­ber of an ex­clu­sive club of in­flu­en­tial de­vel­op­ing na­tions along with Rus­sia, In­dia and Chi­na, col­lec­tive­ly known in eco­nom­ic cir­cles as the BRIC na­tions. Oba­ma is look­ing to re­set the US re­la­tion­ship with Brazil, an emerg­ing eco­nom­ic pow­er that even with­out be­ing hos­tile has an­noyed Wash­ing­ton with its in­de­pen­dent ways. (AP)