The surge represents an 83 per cent increase over the same period of 2018, the agency said on Tuesday, and is the highest since records began in 2013.
Since Thursday, INPE said satellite images spotted 9507 new forest fires in the country, mostly in the Amazon basin, home to the world's largest tropical rainforest seen as vital to countering global warming.
I used to be called Captain Chainsaw. Now I am Nero, setting the Amazon aflame. But it is the season of the queimada.
Brazil President Jair Bolsonaro
Images show the northernmost state of Roraima covered in dark smoke. Amazonas declared an emergency in the south of the state and in its capital Manaus on August 9.
Acre, on the border with Peru, has been on environmental alert since Friday due to the fires.
Fires have increased in Mato Grosso and Para, two states where Brazil's agricultural frontier has pushed into the Amazon basin and spurred deforestation. Bush fires are common in the dry season in some states, but are also deliberately set by farmers illegally deforesting land for cattle and crop farming.
The unprecedented surge in fires has occurred since Bolsonaro took office in January vowing to develop the Amazon region for farming and mining, ignoring international concern over increased deforestation.
Asked about the spread of uncontrolled fires, Bolsonaro brushed off criticism, saying it was the time of the year of the "queimada" or burn, when farmers use fire to clear land.
"I used to be called Captain Chainsaw. Now I am Nero, setting the Amazon aflame. But it is the season of the queimada," he told reporters.
The space agency however, said the large number of fires could not be attributed to the dry season or natural phenomena alone.
"There is nothing abnormal about the climate this year or the rainfall in the Amazon region, which is just a little below average," said INPE researcher Alberto Setzer.
People frequently blame the dry season for the fires in the Amazon, but that is not quite accurate, he said.
"The dry season creates the favourable conditions for the use and spread of fire, but starting a fire is the work of humans, either deliberately or by accident," Setzer said.
Bolsonaro recently fired the director of INPE after he criticised agency statistics showing an increase in deforestation in Brazil, saying they were inaccurate.
"I am waiting for the next set of numbers, that will not be made up numbers. If they are alarming, I will take notice of them in front of you," he told reporters.
Last week Germany and Norway suspended funds to projects designed to curb deforestation in the Amazon.
The decision reflected "great concerns with an increasing deforestation in the Brazilian Amazon," the German embassy told the Folha de SP newspaper.
Norway has worked closely with Brazil to protect the Amazon rainforest for more than a decade and has paid some $1.2 billion ($1.7 billion) into the Amazon Fund.