MEXICO CITY—Mexico's America Movil cellphone carrier has signed an agreement to buy U.S. wireless carrier Simple Mobile.

America Movil says its U.S. subsidiary Tracfone Wireless Inc. will acquire Simple Mobile, which has over 1 million subscribers.

The purchase caps a week of acquisitions by America Movil, Latin America's largest cellphone carrier controlled by Carlos Slim, the world's richest man.

In a statement Thursday, America Movil said it expects to close the deal during the second quarter. It did not provide figures on the cost of the acquisition.

Simple Mobile is a "mobile virtual network operator." Such operators bundle or resell space on radio spectrum or wireless networks.

On Tuesday America Movil announced a euro2.6 billion ($3.4 billion) public offer to acquire an additional 23.2 percent of Dutch carrier Royal KPN NV.