Passengers on a Delta Air Lines flight heading to Atlanta had to be screened a second time after a threat at a Houston airport.

Flight 227 from Houston George Bush Intercontinental to Hartsfield-Jackson International departed at 10:30 a.m. “following a short delay after a non-specific threat, deemed non-credible by authorities and Delta, was made,” Delta spokesman Michael Thomas said.

It is unclear where the threat came from inside the Houston airport, but Thomas said Delta wanted to take precautions to ensure passengers safety.

“The safety and security of Delta’s customers and crew members are always our top priority,” he said.