The heaviest flooding to hit Ecuador in two decades has killed at least 22 people in Quito, inundating homes, swamping cars and sweeping away athletes and spectators on a sports field, officials said Tuesday.

Twenty people are missing and 47 injured, Ecuador's SNGRE emergency service said on Twitter.

Video footage showed torrents of water carrying stones, mud and debris down streets in the Ecuadoran capital, as rescuers helped inhabitants wade through the fast-running currents to safety.

Rain that drenched Quito for 17 straight hours caused a deluge that damaged roads, agricultural areas, clinics, schools, a police station and an electric power substation.