DETROIT — General Motors Co. says it’s shutting down the Saturn brand after an agreement with Penske Automotive Group Inc. to acquire the unit fell apart.

Penske, citing concerns about whether GM could continue to supply vehicles after a manufacturing contract with the automaker ran out, ended talks with GM Wednesday to acquire the brand.

GM CEO Fritz Henderson said in statement that Saturn and its dealership network will be phased out.

In a statement, the Bloomfield Hills, Mich.-based auto retailer says an agreement with another manufacturer to continue producing Saturn vehicles after GM stopped making them fell through, leading Penske to terminate talks with GM.

In June, Penske agreed to take over the Saturn brand and related dealerships. GM agreed to produce the vehicle for a limited period of time.