"We announce an official three-day mourning in the country in memory of the 61 victims of the tragic accident in Vinhedo," the leader wrote on X.
The decree enters into force from the moment of the publication, the document said.
The plane with 57 passengers and four crew members fell on one of the residential areas of the town of Vinhedo on Friday, killing everyone on board. No one on the ground was injured. The causes of the crash are unknown.