HOUSTON - At least four people were stabbed on Monday in "a random act of violence" on the campus of Louisiana Tech University in Ruston, southern US state of Louisiana, authorities said.

One of the four victims was a graduate student, who was reported in serious but stable condition after being airlifted to hospital, local media reported.

The other victims were not students, one of them in critical condition, according to the university.

The suspect, identified as 23-year-old student Jacoby Johnson, fled after the attack but was apprehended by campus police minutes later.

"This appears to be a random act of violence," said the university in a statement.

An investigation is underway.