The chief executive of the automaker Stellantis, Carlos Tavares, has resigned, the company said on Sunday, amid a decline in profits and slumping sales in its key North America region. Mr. Tavares, 66,

The global automaker’s sales in North America declined over the past year because of high-cost models that dealers struggled to sell.

Carlos Tavares, who had been under fire and was expected to leave at the end of his contract, resigned abruptly on Sunday.