WENTZVILLE, Mo. — General Motors will invest $1.5 billion to make what it calls the “next generation” of mid-sized pickups at its plant near St. Louis, the company’s president said Friday.

GM will use the money to upgrade its Wentzville Assembly and Stamping Plant in preparation for the new products, GM President Mark Reuss said at a news conference inside the plant. The company already produces the Chevrolet Colorado and GMC Canyon pickups there.

Reuss said the investment is expected to help retain 4,000 jobs at the plant. The company has about 4,300 total workers in Wentzville and any job losses will come through attrition, said Glen Kage, president of United Auto Workers Local 2250, which represents the workers.

A GM spokeswoman confirmed that no jobs will be cut.

GM will invest about $1 billion to upgrade the plant itself. The rest of its investment is expected to be used for things such as machinery for outside companies that supply parts to the plant.

“It’s a big deal,” Reuss said. “I feel good about this. I really do.”