RIO DE JANEIRO (AP) — Heavy rains blamed for the deaths of at least four people continued to fall on Rio de Janeiro on Tuesday as officials closed schools and urged people to avoid non-essential traffic.

Torrents of water gushed down streets, sweeping up cars and uprooting trees following rains that began around rush hour Monday evening. Mayor Marcelo Crivella said the Brazilian city faced a "crisis" and said heavy rains would continue.

City officials said 6 inches (152 millimeters) of rain fell in just four hours Monday night, more than the average for the whole month of April. The botanical garden neighbourhood, a touristic destination, was one of the most badly hit areas, receiving 9 inches (231 millimeters) in a 24-hour period.

Local television stations showed firefighters in that neighborhood wading through knee-deep water pulling a small boatload of children evacuated from a schoolbus on a flooded street.

Sirens rang in 20 flood-risk areas of the city, alerting people to make their way to pre-established safe spaces. But Crivella said they weren't triggered in the Babilonia slum, which sits on a hill behind the city's iconic Sugarloaf mountain. The fire department said two women there died in a mudslide and local residents complained about the lack of warning.

A third person drowned, officials said, but the circumstances in which a fourth person died remained unclear.

Hillside slums are particularly vulnerable to mudslides and city officials said more than 100 communities have been identified as having "high geological risks."