Houston-area travelers returning through George Bush Intercontinental Airport described fear and uncertainty after a wave of cartel violence broke out in parts of Mexico, prompting U.S. officials to urge Americans in certain regions to shelter in place.

Passengers arriving at Bush Airport Monday night said simply making it onto a flight felt like a relief after chaos unfolded near popular tourist destinations, including Puerto Vallarta and Guadalajara.

For some travelers, walking through the airport doors in Houston marked the end of a frightening ordeal.

Thomas Brooks said he had just arrived in Puerto Vallarta when the situation suddenly escalated.

“As we were about to get on the plane, they told us to run to the corner and hide,” Brooks said.

He said passengers were evacuated onto the airport tarmac as confusion spread through the airport.

“It was a scary situation, but you’re in survival mode,” Brooks said. “You just try to find a way to get out of there and get safe.”

His wife, Sherry Brooks, said they prepared for the possibility of gunfire while waiting.

“I told him, ‘Baby, whenever you hear — if we hear gunfire — just drop down. Don’t think about it, just get down,’” she said.

Other travelers passing through Houston were forced to change plans as flight disruptions stranded passengers away from their final destinations.

“It’s terrifying,” said Jose Trejo, who was traveling from Puerto Vallarta and using Houston as a layover. “We’re not even from Texas. We’re from Chicago, but we had to come here because there’s no flights to Chicago until Wednesday.”

Trejo said boarding a plane brought an overwhelming sense of relief.

“When I got on the plane today — oh man — I was stoked,” he said.

Wendy Burdick, who spends several months each year in Puerto Vallarta, said the shutdown and violence were unlike anything she had previously experienced there.

“We were sure we weren’t going to be able to get out, even though we had a pre-arranged flight, because the airport was closed yesterday and this morning,” Burdick said.

She said she saw the impact of the violence firsthand while traveling to the airport, passing a burned bus and a damaged semi-trailer along the roadway.

“Oh yeah, incredibly relieved,” she said of finally leaving. “We were flabbergasted we got out.”

RELATED: Texas coordinating with feds as Americans told to shelter in place amid Mexico violence

RELATED: Who ‘El Mencho’ was and what to know about the cartel he led

The unrest began after a Mexican military operation in the state of Jalisco that resulted in the death of “El Mencho,” the leader of one of Mexico’s most powerful drug cartels. Authorities said the cartel leader was killed during a shootout with soldiers.

Following the operation, cartel members retaliated by burning vehicles and setting up roadblocks across several areas. While much of the violence had subsided by Monday night, gunfire was still being reported in some locations, including Puerto Vallarta and Guadalajara.

Travel disruptions are expected to continue for several days as airlines work to stabilize schedules.

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