The school, on its Web site, said the chase near campus involved the Texas Department of Public Safety and the Border Patrol.
DPS spokeswoman Tela Mange told The Associated Press that officers were pursuing a vehicle that reached campus, then "everybody ran from the vehicle."
The Corpus Christi Caller-Times reported in its online edition that law officers were seeking about a dozen suspected illegal immigrants who fled after a traffic stop near Kingsville.
A DPS trooper had stopped a pickup for speeding. The driver pulled over and about 12 people got out of the truck and fled, according to Trooper Eric Hinojosa.
The truck driver said he was forced at gunpoint to transport the truckload of illegal immigrants to Kingsville, Hinojosa said.
The driver was turned over to Border Patrol agents. His name was not immediately released.
No one was allowed leave campus when the lockdown began. Students and staff were advised to stay inside buildings. Campus activities were canceled Wednesday night, but the school would return to its regular schedule Thursday, according to Scoggins.
School president Rumaldo Juarez told The AP, in a cell phone interview after the lockdown ended, that the safety of students, faculty and staff was the utmost concern.
"We took the appropriate measures that we needed. Our staff reacted the way we needed to react, the way we had rehearsed," said Juarez, who was on campus during the lockdown.
The school has an emergency e-mail alert and voice messaging system, Scoggins said.
A&M-Kingsville has enrollment of about 6,200 and 1,100 faculty and staff, on a campus located 40 miles southwest of Corpus Christi.