Thunderstorms have killed seven people and left more than half a million homes and businesses without power in south-eastern Texas.

Residents in the area could be without power for weeks after Thursday's storm, which packed 110mph (177km/h) winds, BBC reported.

The deaths were mostly caused by downed trees and power lines and lightning. The storm has moved on to neighbouring Louisiana with flood warnings in place for the Gulf Coast.

In an update on Friday night, officials announced the deaths of three more people, taking the toll to seven.

In Friday's news conference, Texas Judge Lina Hidalgo, the top government executive in Harris County, said that at least two tornados hit the region on Thursday night.

In Houston, traffic lights were out on Friday, office windows blown through and glass strewn across the city's streets.

The Houston Independent School District district cancelled school on Friday.

Flash floods and severe thunderstorm warnings were issued for multiple counties, according to Houston's National Weather Service office.

On Friday evening, about 600,000 homes and businesses were without electricity, down from nearly one million customers one day earlier.

This is the second time in six weeks that a deadly storm has swept through the Houston area. Last month a tornado hit the suburb of Katy, killing one person and injuring 10.