MEXICO CITY - GUNMEN killed 15 people at a car wash on Wednesday in a Mexican Pacific coast state where drug-gang violence has risen this year. It was the third massacre in Mexico in less than a week.

The gunmen in three vehicles drove up to the car wash in the city of Tepic and opened fire without provocation, said Fernando Carvajal, public safety secretary of Nayarit state, where the city is located. Fifteen men were killed and three people were injured. The motive was not immediately clear but investigators suspect it was the work of organised crime, Mr Carvajal told reporters.

He said most of the victims were recovering drug addicts and worked at the car wash. One victim, however, had just driven up to the business in a motorcycle and appeared not to have worked there, and another body was found at a nearby fruit stand.

Mr Carvajal said the owners of the business have another car wash in the city where a man was killed on Tuesday, and police were investigating whether the attacks were linked. Nayarit Governor Ney Gonzalez told Radio Formula that investigators believe some of the victims had been washing a stolen car.

President Felipe Calderon, speaking at a forum on security, called for a minute of silence for the victims of the Tepic attack and two other massacres that have occurred since Friday: an attack on a birthday party that killed 14 young people in the border city of Ciudad Juarez, and a shooting at a drug rehab centre in Tijuana that killed 13 recovering addicts.

The three attacks did not appear to be related. Such mass shootings have become increasingly common in Mexico, where drug-gang violence has surged in recent years.

15 die in car wash massacre