Nearly a dozen bystanders and first responders rushed to the scene of a private jet crash on a Texas motorway on Tuesday to help free trapped passengers.

Using what appeared to be a shovel and a sledgehammer, the passers-by and emergency officials helped several passengers escape through an opened door, video shows.

The aircraft was flying from Los Cabos, Mexico, to Austin, Texas, when it reported major mechanical issues to Laredo airport, Gilberto Sanchez, the airport's director, told the New York Times.

One of the six people on board died in the crash, said police. The five survivors were taken to hospital and are in a stable condition.

The individual who died has yet to be identified.

One vehicle was struck by the aircraft as it crashed on to the motorway, though it is unclear what part of the plane struck the vehicle, said Jose Baeza, an investigator with Laredo Police Department.

Videos of the aftermath shared on social media show thick smoke and flames surrounding the plane. Five first responders were ultimately treated for smoke inhalation, said Baeza.

The crash happened near Laredo airport, 150m (240km) southwest of San Antonio.

The crash has forced the major motorway, Loop 20, to shut down while the investigation proceeds. Baeza said it was expected to remain shut to traffic on Wednesday as the investigation, which will include the FBI and the National Transportation Safety Board (NTSB), continues.