The refusal came just days after a spat between Lula and Ukraine President Volodymyr Zelensky at the G7 summit in Japan, where a planned meeting between the pair fell through.

"I thanked (Putin) for an invitation to go to the International Economic Forum in Saint Petersburg and replied that I cannot go to Russia at this time," wrote Lula on Twitter about the event scheduled for June 14-17.

"But I reiterated Brazil's availability, alongside India, Indonesia and China, to speak with both sides of the conflict to seek peace."

Ukraine has been at war with its much larger neighbor Russia since Putin ordered an invasion in February 2022.

While many Western countries have sent weapons to Ukraine to help it defend itself and have hit Moscow with financial sanctions, Lula instead has tried to position himself as a mediator, creating a group of nations seeking to produce a negotiated peace deal.

After their proposed meeting fell through in Japan, Lula first said he was "upset" before then claiming that he did not see a point in meeting Zelensky, saying neither he nor Putin appeared to want peace.

"For now, they're both convinced they're going to win the war," he said.

Last year, Lula came under fire for claiming that Zelensky was "as responsible" for the war as Putin.