BROWNSVILLE, Texas — At least eight people were killed after the driver of a vehicle plowed into a crowd of migrants on Sunday outside a center that serves homeless people in this city near the border with Mexico, the authorities said.

Seven of the people who were struck “were dead on the spot” when police arrived, Martin Sandoval, an investigator with the Brownsville Police Department, said. At least 10 people were injured, one of whom was airlifted to an area hospital. One person died later, the department confirmed on Sunday night.

Judge Eddie Treviño Jr. of Cameron County said the group was outside the Ozanam Center, near a bus stop, when a Range Rover barreled into them around 8:30 a.m. local time. The driver was injured and taken to a hospital, Judge Treviño said.

The driver, who was not publicly identified and was believed to be in his 30s or 40s, was charged with reckless driving and was detained, but more charges could be added, Mr. Sandoval said.

The man had been speaking to investigators in both English and Spanish, but he had also given the police different names and had not submitted to a breathalyzer test or provided his fingerprints, Mr. Sandoval said.

Police were still trying to determine how fast the vehicle was going and whether the crash was intentional. The police have ordered a warrant for the driver’s blood to determine if he was intoxicated, Mr. Sandoval said.

Police were also looking into reports that he had uttered anti-immigration remarks.

Brownsville, a border town in the Rio Grande Valley of Texas, is no stranger to immigration. Situated in one of the poorest regions in the country with a majority Hispanic population, Brownsville has seen a bigger number of people crossing, with up to 1,500 migrants a day arriving in recent days by some estimates.

Judge Treviño said the crash scene was “very graphic” based on videos he had seen of the aftermath and a briefing he had received.

“They looked like very serious injuries,” he said. “It’s a tragedy either way, but if it was intentional, it’s worse.”

All of the victims were believed to be migrants from Venezuela, many of whom had been coming to the border in anticipation of the lifting of Title 42, a Trump-era pandemic rule that allowed for the easy expulsion of migrants.

Victor Maldonado, executive director of the Ozanam Center, said the driver ran a red light before crashing into the crowd of about 20 people. “All bodies just started going everywhere, all directions,” he said.

A group of people detained the driver, who tried to flee, said Eyder Hernandez, one of those who stopped him. On the journey from Venezuela to Texas, the group of migrants became like a family, he said.

Michael Eduardo de Aponte Fonseca, who is from Caracas, Venezuela, said the driver had yelled anti-immigration insults to the group while he fled. One of the people hit by the car fell on Mr. Fonseca, he said.

“I saw what happened around me, and I didn’t want to see more,” he said. “I grabbed my things, and scared and in shock I crossed the street.”

The Ozanam Center is a shelter frequented by migrants who stay for only a few days while they work to secure travel elsewhere, Mr. Maldonado said.

He said they stay in Brownsville to “do odd jobs and get a little money so they can move on.” But, he added, “Some of those folks tonight will not reach their destination.”

Lauren McCarthy, Joshua Needelman and April Rubin contributed reporting.