Biden visits storm-battered Texas

US President Joe Biden has visited a food bank, health centre and emergency operations facility to assess recovery efforts from a deadly Texas winter storm.

Biden and wife Jill landed in Houston on Friday where he met Republican Governor Greg Abbott and Houston Mayor Sylvester Turner to discuss the recovery from last week's storm.

The weather system caused serious damage to homes and businesses, left millions without power or clean water for days and killed at least two dozen.

At the Houston Food Bank, the largest in the country serving more than 1.1 million people, Biden saw rows of packaged food, from pasta to applesauce, stacked for dispatch and volunteers pull food from boxes on conveyers and put them in containers for delivery.

He visited an emergency operations centre in Harris County, where roughly 50 per cent of the county's 4.9 million residents were without power.

"As my mother would say to you, you're doing God's work," he told workers there.

Biden has sought to bring consolation and empathy to the hard-hit state, which leans heavily Republican.

When he visited a vaccination centre, he repeated his message.

"We're not here as Democrats or Republicans. We're here today as Americans."

Biden also said his administration had given out 50 million shots of vaccine out of the 100 million the White House promised would be delivered in the first 100 days. He said the effort was "weeks ahead of schedule".

"America will be the first ... in the world to get that done," he said.

In five weeks, the United States had administered more shots than any country, Biden said.

The United States has the highest COVID-19 death toll at more than 500,000 and is still recording the most infections and deaths per day.

Biden also delivered a warning with his message of hope and progress.

"Cases and hospitalisations could go back up as new variants emerge and it's not the time to relax," he said.

Earlier in the day, Biden's deputy national security adviser, Elizabeth Sherwood-Randall, laid responsibility on the Texas government for foregoing energy regulation that could have left it better prepared.

"Texas has chosen not to make the kinds of decisions that would provide for the supplies that you would keep for an emergency, that is, to invest in a kind of resilience that other states which are regulated are required to invest in," she said.

"They don't have the backup in terms of supply or generation capability that they needed to have in this crisis," she said.

For 10 days this month, Texas was hit by an unusually prolonged period of very low temperatures.

Electricity consumption surged, while many generating units failed to start up owing to frozen instrumentation.

The state's Republican leaders have come under fire for not heeding warnings that the Texas power grid needed significant upgrades to defend against deep freezes.