Five people went missing this week while distributing telephone directories in the western Mexican state of Michoacan, authorities said Friday.

"They are four people from the firm Seccion Amarilla and a driver," a spokesman for the state Attorney General's Office told Efe, adding that an extensive ground and air search was already under way.

The five individuals were last seen Tuesday after leaving the Nueva Italia neighborhood in the city of Apatzingan.

A missing persons report was filed Thursday.

The Seccion Amarilla employers were delivering phone books, Marisela Baños Angeles, sister of the team's leader, Miguel Angel Baños, told MVS radio.

News of the disappearances follows the release Wednesday of nine polling company workers who were abducted in Apatzingan.

Six employees of the Consulta Mitofsky polling organization disappeared last Saturday, while three Parametria workers went missing around noon on Monday.

Police, soldiers and members of the public took part in the search for the missing pollsters.

Michoacan has been experiencing a wave of drug-related violence blamed on the splintering of La Familia Michoacana, considered one of Mexico's most powerful drug cartels.

One of the resulting factions, which retains the name La Familia, has been battling an offshoot that calls itself Los Caballeros Templarios (The Knights Templar).

The central government deployed 1,800 additional Federal Police officers in Michoacan, President Felipe Calderon's home state, in early July to fight the state's criminal organizations.

Michoacan is on Mexico's Pacific coast, which is used by smugglers to bring South American cocaine and heroin into the country.

The drugs are then smuggled via the Pacific corridor or through central Mexico into the United States, the world's largest consumer of illegal drugs.