Gunmen kill prominent politician-union leader in Mexico Officials say an 83-year-old union leader and former federal senator has been assassinated in central Mexico

MEXICO CITY -- Officials say an 83-year-old union leader and former federal senator has been assassinated in central Mexico.

The Guanajuato state prosecutor's office has issued a statement promising to deploy all the resources necessary to investigate Saturday's killing of Gilberto Muñoz Mosqueda.

Local news media say gunmen ambushed his car as he travelled through the city of Salamanca.

Muñoz had headed a chemical and petrochemical workers union for about four decades. He also had been a federal senator for the then-ruling Institutional Revolutionary Party and had served several terms in the federal congress. He also was a senior official in the main country's main labor federation, the Mexican Confederation of Workers.

The motive for the slaying wasn't immediately clear.