The IRNA news agency was the first to publish that the visit, which sparked demonstrations in Brazil, had been cancelled without disclosing reasons for the move.
"Dr.Ahmadinejad's trip to three countries in Latin America which was supposed to be on Tuesday will be postponed," the presidential website said.
The Iranian president announced the trip had been cancelled in a message to his Brazilian counterpart, Luiz Inacio Lula da Silva, minutes before the start of an official news conference at the Brazilian foreign ministry. In the message, the Iranian leader said he was ready to visit Brazil after Iranian presidential polls scheduled for June 12, 2009.
Hundreds of people took to the streets in Brazil to protest the visit, accusing the Iranian leader of supporting terrorism and suppressing civil liberties in his country. They also demanded that the Brazilian government withdraw Ahmadinejad's invitation.
Ahmadinejad was also expected to travel to Venezuela and Ecuador on Thursday and Friday.