Security was reinforced in the capital Brasilia and police started blocking access to the central mall where thousands are expected to march on Tuesday, supporting Bolsonaro in his clash with the judiciary over changes to Brazil's voting system.
The demonstrations are "stoking fears of a coup d'état in the world's third-largest democracy," the letter warned. Congress and the courts also resisted Bolsonaro's attempt to introduce paper voting receipts as a backup of an electronic voting system, which he argues is vulnerable to fraud. The electoral court maintains the system is transparent and safe.
Brasilia will have 5,000 police and military personnel on hand to maintain order at the march outside Congress, where Bolsonaro is scheduled to appear on Tuesday morning.
Pro-freedom, pro-democracy