The announcement came on the day Brazil celebrates its Amazon region, home to the world's largest tropical rainforest, the preservation of which is seen as essential to soaking up carbon emissions responsible for global warming.
Environmentalists say Indigenous groups are the best guardians of the rainforest and deforestation data shows that the forests on their reservations are the best conserved.
Lula, who pledged to legalize the greatest number of reservations possible, has so far signed decrees recognizing eight Indigenous territories since taking office in January.
It is a race against time as Brazil's Congress is pushing through legislation that would restrict the recognition of Indigenous land claims, a move backed by the country's powerful farm lobby.
The Supreme Court, however, is expected rule that the cut-off date for claiming ancestral lands that were not lived on in 1988 is unconstitutional for denying recognized Indigenous rights.
The reservations legalized by Lula on Tuesday are the Acapuri de Cima and the Rio Gregorio Indigenous territories in the states of Amazonas and Acre, respectively.
Some 500 Kokama people live on 19,000 hectares (47,000 acres) of rainforest in the first reservation, and 2,000 Katukina and Yawanawá people live on 187,944 hectares (46,420 acres) in the second.
Lula plans to recognize six more reservations by the end of the year, said Indigenous Peoples Minister Sonia Guajajara.
She said the government's plans to legalize more reservations has led to threats of violence against Indigenous communities based on unfounded rumors.
"They are saying that the demarcations will take land away from farmers, and even villages and towns, which is causing terror," she told the Folha de S.Paulo newspaper.
(Reporting by Anthony Boadle; Editing by Sandra Maler)
By Anthony Boadle
