Brazilian banks are scrambling to assess the domestic fallout from sweeping U.S. sanctions against a Supreme Court justice who oversees a criminal trial against an ally of President Donald Trump, as legal teams weigh how the move to isolate the judge financially could ripple through Brazil's financial system.

Brazilian Supreme Court Justice Alexandre de Moraes, who is presiding over the coup trial against former President Jair Bolsonaro, vowed Friday to "ignore" US sanctions against him.