A severe storm packing hurricane-force winds pummeled Houston on Thursday, killing at least four people, blowing windows out of high-rise buildings and leaving some 800,000 homes without power as much of the city was plunged into darkness, the mayor said.

Much of downtown Houston and its commercial district were littered with fallen power lines and glass from shattered windows following the storm, with traffic and street lights knocked out across the city, the mayor, John Whitmire said in an interview on local television station KRIV.

Speaking from the city's emergency operations center, Whitmire said the thunderstorm raked the Gulf Coast city in southeast Texas, the state's most populous urban center, with winds howling at 129-161 kilometers per hour.

He urged members of the public to stay indoors and to especially avoid the heavily hit downtown area, which he said was left darkened and strewn with broken glass.

ALSO READ: Massive winter storm: US airlines cancel over 2,000 flights

"The message right now is to stay home," he said, adding that public schools would be closed on Friday and that local authorities were asking all non-essential workers to likewise take the day off.

The mayor said at least four storm-related fatalities had been confirmed, mostly from fallen trees. "Over 800,000 families are without power right now," he added.

Whitmire delivered similar initial storm assessments during a brief televised news conference carried live a short time after his interview.

The mayor said the severe weather had caught many residents by surprise, recounting that he was attending a little league baseball game when the storm hit, "and we had very little time to get to cover."

READ MORE: Death toll tops 20 as storm takes aim at eastern US

The National Weather Service also issued a flood watch for the Houston area from heavy rains associated with the storm.