Authorities in Mexico have confirmed that a federal legislator was killed and burned after being abducted in broad daylight.

Gabriel Gomez Michel, 49, was driving to the airport in the western state of Jalisco on Monday when several cars intercepted his 4WD vehicle, the authorities said on Wednesday.

The former pediatrician's body was found early on Tuesday in the neighbouring state of Zacatecas inside the charred remains of his vehicle, alongside the burned corpse of his assistant.

The Jalisco prosecutor's office said forensic experts positively identified the bodies of Gomez Michel and Heriberto Nunez Ramos.

In a statement, the office said authorities were investigating who was behind the "double homicide".

Arturo Nahle, the chief prosecutor of Zacatecas, said no bullets were found on the bodies or the car and that the corpses were too badly burned to tell how they were killed.

The murder resembled the "modus operandi" of gangs, Nahle said, telling Radio Formula "it is a classic execution by organised crime".

Security cameras captured the abduction, showing cars flanking Gomez Michel's 4WD vehicle as a man in a red shirt points at the car's window on the road outside Guadalajara.

Gomez Michel's wife had called the authorities to report his disappearance.

His home state Jalisco is a bastion of the Jalisco New Generation drug cartel. Nahle said the Gulf Cartel is present in Zacatecas.

No prior threats

Officials said Gomez Michel had not received threats before his killing.

Local politicians have often been the targets of attacks or threats during Mexico's drug war, with at least 30 mayors killed since 2006, but attacks against federal deputies are less common.

Moises Villanueva, a PRI legislator, was killed in 2011.

El Universal newspaper documented attacks against five other federal legislators since 2006, and a foiled plot against two others last year.

In March 2013, Jalisco's tourism secretary was killed in his 4WD vehicle in Zamora, a popular tourist spot on the Pacific coast.

About 80,000 people have been killed since troops were deployed to crack down on drug cartels in 2006.

Gomez Michel, who was mayor of El Grullo in 2010-2012, belongs to Mexican President Enrique Pena Nieto's Institutional Revolutionary Party (PRI).

Pena Nieto said on Tuesday that murders had slipped by 29 percent in the first half of 2014 compared with the same period in 2012, the year he took office.