Two people were killed Friday when a small plane crashed on a major avenue in Brazil's economic capital Sao Paulo and skidded into a bus, authorities said.

It was unclear if the aircraft had been attempting an emergency landing shortly after taking off. It slid hundreds of meters along the avenue and hit a bus before exploding, firefighter chief Ronaldo Melo told journalists.

The pilot and sole passenger were killed in the accident, which happened shortly after the King Air F90 took off from the Campo de Marte airport, which handles domestic flights.

The passengers of the bus managed to escape, and six were injured, said Melo.

Images broadcast on local television showed thick plumes of smoke billowing into the air, however firefighters quickly got the blaze under control.

Investigators are at the scene "taking photos and interviewing people who witnessed the aircraft crash" to establish the circumstances of the accident, Melo said.