US auto giant General Motors will invest $3.6 billion over four years to expand and modernize four plants in Mexico, the company said on Thursday.

With this investment, GM will have spent $5 billion in Mexico between 2013 and 2018, generating 5,600 direct and 40,000 indirect new jobs, said the company's chief in Mexico, Ernesto Mariano Hernandez.

"It is a ratification of the commitment of General Motors in Mexico," he said at an event alongside Mexican President Enrique Pena Nieto.

The factories are located in the states of Mexico, San Luis Potosi, Coahuila and Guanajuato. They produce about 647,000 vehicles annually in Mexico - 80 percent of which are exported. The plants also produce an annual average of 890,000 motors in Mexico along with 1.2 million transmissions.

GM says it currently employs about 15,000 people in its Mexico operations. Another 105,000 people work at plants that supply GM, which spends about $14 billion a year on purchasing in the country.

Mexico is Latin America's biggest car producer and the seventh in the world, up from the eighth in 2013. Cheap labor, proximity to the United States, and free trade agreements with several nations have made it an increasingly attractive location for foreign car manufacturers.