Trying to clear a flooded storm drain of debris, a nine-year-old boy and his uncle were pulled underwater and sucked into the drain in Brazil in an incident captured on video.

In the mobile phone video, which went viral in the South American country, the boy and four men are seen playing in a pool of muddy flood water as they try to clear plants and other rubbish from a backed-up storm drain. The boy and his uncle are suddenly dragged underwater as the pipe's passageway clears up.

The boy's aunt, who filmed the potentially deadly scene, screams in horror as the two disappear under the brown water.

Another family member captured the frightening images from a different angle.