A POWERFUL tornado swept over a small city in Uruguay, ripping up houses, hurling cars into the air and killing at least four people, while seven others were seriously injured.

Residents of Dolores, a city of 20,000 people about 165 miles west of Montevideo, shot images of their homes and cars being swept up by the tornado on Friday and posted them on social media.

"The president has ordered the deployment of all the resources in the state to attend to the situation in Dolores," said Juan Andres Roballo, an official with the Uruguayan president's office. The city was declared an emergency zone.

Mr Roballo said a good part of the population had lost their homes and at least two children were seriously hurt and had been transferred to the capital for treatment.

Fire department spokeswoman Mariela Vivone told Channel 12 television that two of the dead were killed by flying cars carried by the winds.

Local media outlets reported that some residents took advantage of the chaos to loot shops.

Mr Roballo said the police and military presence in the area would be increased.