Two children were killed and about a dozen people were injured in Texas Saturday after powerful storms spawned at least one suspected tornado and damaged several homes, authorities said.

The Angelina County Sheriff’s Office said an 8-year-old and a 3-year-old died when strong winds toppled a tree onto the back of their family’s car in Lufkin while it was in motion. Capt. Alton Lenderman said the parents, who were in the front seats, were not injured.

Lufkin is about 115 miles northeast of Houston.

The storms are part of a large system that moved through the southern United States, knocking out power to thousands and causing some flash flooding. The weather service said the system is expected to shift to the Ohio Valley and the Southeast on Sunday.

Meteorologist John Moore said a possible twister touched down Saturday in the Vicksburg, Mississippi, area. No injuries have been reported

Winds of up to 60 mph (96.56 kph) were reported in Cherokee County, Texas.