A Texas man accused of mowing down a group of pedestrians at a bus stop killing eight people near a shelter for migrants and the homeless has been charged with manslaughter, police said.

Authorities believe driver George Alvarez, 34, lost control after running a red light on Sunday morning and ploughed into a crowd of Venezuelans near the Ozanam Centre in Brownsville.

Authorities were still investigating whether the crash, which happened at around 8.30am local time, was intentional.

Brownsville police chief Felix Sauceda said six people died on the scene and 12 people were critically injured. Officials said the death toll later rose to eight.

At a news conference on Monday morning, he said the SUV jumped a red light, lost control, flipped on its side and struck 18 people.

Alvarez, of Brownsville, has been charged with eight counts of manslaughter and 10 counts of aggravated assault with a deadly weapon.

Mr Sauceda said Alvarez allegedly tried to flee, but was held down by several people on the scene.

He added that officials are awaiting toxicology reports to determine whether Alvarez was intoxicated. He received bonds totalling $3.6m.

Sister Norma Pimentel, executive director of Catholic Charities of the Rio Grande Valley, said victims struck by the vehicle were waiting for the bus to return to downtown Brownsville after spending the night at the overnight shelter.

Most of the victims were Venezuelan men, Ozanam Center shelter director Victor Maldonado said.

Brownsville has seen a surge of Venezuelan migrants over the last two weeks for unclear reasons, authorities said.

The Ozanam shelter is the only overnight shelter in the city of Brownsville and manages the release of thousands of migrants from federal custody.

The shelter can hold 250, but many who arrive leave the same day. In the last several weeks, an uptick in border crossings prompted the city to declare an emergency as local, state and federal resources coordinated the enforcement and humanitarian response.

While the shelter offers migrants transportation during the week, they are also free to use the city’s public transportation.