Four people have died in the US state of Texas as Tropical Storm Beryl continues to move across the state, while millions remain without power. continues to move across the state.

The operator said the outage was likely to last several days, noting that some 2 to 3 million homes were affected by the outage.

Beryl made landfall as a hurricane on Monday morning near the town of Matagorda, Texas, about 130 kilometres southwest of Houston, but has since lost strength.

The National Hurricane Centre has issued warnings for parts of Texas and Louisiana for more tornadoes, flash flooding and high winds.

Meteorologists expect Beryl to continue to move northeast over the next few days as it weakens further.