Deforestation in the Brazilian Amazon fell by 31 percent in the first five months of President Luiz Inacio Lula da Silva's administration versus the same period last year, officials said Wednesday.

Satellite monitoring detected 1,986 square kilometers (767 square miles) of forest cover destroyed in Brazil's share of the world's biggest rainforest from January to May, down from 2,867 square kilometers for the same period in 2022, according to the national space agency's DETER surveillance program.

The figures from space agency INPE were welcome news for environmentalists pinning their hopes on veteran leftist Lula, who took office on January 1 vowing to fight for zero illegal deforestation after a surge in clear-cutting and fires in the Amazon under his far-right predecessor, Jair Bolsonaro (2019-2022).

Under Bolsonaro, an ally of Brazil's powerful agribusiness sector, average annual deforestation in the Brazilian Amazon increased by more than 75 percent versus the previous decade.

Lula marked World Environment Day on Monday by announcing a sweeping new plan to combat deforestation, with hundreds of targets and objectives, including the immediate seizure of half the territory being illegally exploited for logging, farming, mining or other activities on protected lands.

"Brazil plays a major role in the balance of our planet's climate, largely thanks to the Amazon," Lula said.

"Preventing deforestation in the Amazon also helps reduce global warming."

Experts say the new government's real test on deforestation will start in the coming months, with the onset of drier weather in the Amazon from around July -- typically peak season for deforestation and forest fires.

The Lula administration has suffered a series of setbacks on the environment this week at the hands of Brazil's Congress, in which conservative foes of Lula hold the majority.

Last week, lawmakers passed bills cutting the powers of the environment and Indigenous-affairs ministries and dramatically curbing the protection of Indigenous lands.