MSCI's Latin American equities index .MILA00000PUS fell 1.2%, while its regional currency index .MILA00000CUS slipped 0.7%. Both benchmarks were heading for weekly losses.
Markets also digested Warsh's Jackson Hole remarks, in which he reiterated his focus on bringing inflation back to the central bank's 2% target, while offering little guidance on future policy moves. Traders subsequently added to bets on a September rate hike by the U.S. central bank.
The dollar =USD rose 0.6% to a two-week high, extending a recovery from sharp losses last week when U.S. Treasury bond-buyback plans revived talks of "dollar debasement" trades.
Brazil's Bovespa .BVSP dropped 0.2%, on track to snap a seven-session winning streak, while the real BRL= weakened 0.9%.
Fiscal worries remain in focus as President Luiz Inacio Lula da Silva said late on Thursday that Brazil's rising public debt would not concern him in a potential new term. Lula, who is seeking reelection in October, blamed part of the increase on the country's 14% benchmark interest rate.
Brazil's gross debt has risen more than 10 percentage points since Lula took office, reaching 81.9% of GDP in June, central bank data showed.
"The challenge is that Brazil's fiscal situation may need to deteriorate further before policymakers are forced to address it," said Alejo Czerwonko, chief investment officer for emerging markets at UBS Global Wealth Management.