RIO DE JANEIRO - Brazil's former President Luiz Inacio Lula da Silva resumed his political schedule on Thursday, after recovering from a four-month-long cancer treatment.

Walking with the aid of a cane, Lula attended a seminar on Brazil-Africa cooperation, organized by Brazil's Development Bank (BNDES).

After months without any public speeches, the former President talked about the challenges of cooperation and expressed optimism about Brazil's future.

"I was optimistic as President, and I remained optimistic with President Dilma (Rousseff). I am even more optimistic now. This country is preparing to become one of the world's great ones," he said.

Lula called for more cooperation between Brazil and African countries, and stressed the importance of sharing technological knowledge.

"We cannot see African countries as mere providers of ore, gas and oil. We want to share technology. We can do much more than what is being done," he said.

In addition, the former President criticized the measures taken by developed countries during the economic crisis, saying they punished workers who are the crisis victims, but benefited the financial market and the large corporations, which should be blamed for turmoil.

"Rich countries gave all their support to the financial system and nothing to the poor," he said.

Lula was diagnosed with throat cancer last October and was immediately put under treatment. He had undergone several rounds of chemotherapy and radiotherapy treatments and the physicians claimed in March that he was cancer free.