Officials in Sao Paulo on Sunday reported seizing 22 tons of drugs, recovering 427 stolen or missing vehicles, and arresting 2,800 people in the first 24 days of "Operation Choke" — a massive anti-crime effort focused primarily on Brazil's largest city and the surrounding area.

According to the state government, highway police also managed to recover 22 tons of stolen iron on Friday.

Operation "Choke" or "Sufoco" in Portuguese was launched in early May to clamp down on crimes in the city of 12 million, with both normal and military police taking part in the effort. The authorities nearly doubled the number of security forces on the streets of from 5,000 to 9,700. The clampdown has no end date.

Governor warns criminals to 'change their profession' or leave

While announcing the operation, Governor Rodrigo Garcia warned criminals to "either change their profession or change their state" because the police would be after them.

A major focus of the clampdown are also crimes committed by thieves posing as delivery couriers, who often use backpacks from delivery services to sneak up on their victims. On Friday, however, delivery drivers staged a protest against police tactics, saying that thousands of legitimate drivers were pulled over by police.

Brazil has been struggling with high crime rate for many years. At the same time, many observers accuse the police of using brutal tactics in poor neighborhoods. The news of the crime clampdown comes just days after a police raid on a favela in Rio de Janeiro, Brazil's second most populous city, left over 20 people dead.

Edited by: Mark Hallam