Heavy rainfall battered Chile's capital Santiago and surrounding areas on Thursday, triggering mudslides that swept cars through streets, inundated homes, forced evacuations and injured at least six people, authorities said.

President José Antonio Kast declared a state of emergency in Las Condes, a wealthy suburb east of Santiago, granting government agencies greater powers to respond to the situation as torrential rain turned major roads into impassable waterways.

Catalina San Martín, mayor of the district, said 14.4 centimetres (5.7 inches) of rain had fallen in recent days, nearly nine times the average rainfall for October, leaving the area “totally saturated.”

The Mapocho River, which flows through Santiago, overflowed its banks, prompting evacuation orders. Chile's disaster-response agency placed 10 other districts on high alert over the risk of further landslides and ordered schools to remain closed on Friday.

Earlier storms this week had already damaged dozens of homes across central Chile and left nearly 12,000 customers in Santiago without electricity, officials said. The heavy rainfall was expected to ease on Friday.

No deaths were reported on Thursday. The injured included a one-year-old child who suffered broken bones, officials said. Firefighters reported rescuing or evacuating more than 1,000 people.

The flooding comes as a powerful El Niño weather phenomenon gains strength. The naturally occurring warming of tropical Pacific waters disrupts rainfall patterns worldwide and often brings wetter spring conditions to the Southern Hemisphere.

The World Meteorological Organization said on Thursday that this year's El Niño was expected to peak in December and could be among the strongest recorded since at least 1950.