CUPERTINO  (AP) — Apple began selling a new iPad Mini on Tuesday without the usual fanfare.

Apple usually announces the availability date in advance, allowing loyal customers to line up at stores overnight to be among the first to buy one. This time, Apple quietly issued a news release on its immediate availability.

Supplies also are limited. People had to order them online to pick them up at Apple's retail stores.

This suggests Apple may be having problems producing enough iPad Minis. Apple CEO Tim Cook acknowledged during a conference call two weeks ago that "it's unclear whether we will have enough for the quarter or not."

The new Mini is the first version of the smaller iPad to feature a high-resolution display that Apple calls Retina. It also includes a power-efficient A7 chip, along with faster wireless and expanded LTE cellular connectivity.

It's available in silver or gray. Wi-Fi-only models will start at $399 for a 16-gigabyte gigabyte model, while cellular-capable models will start at $529 for the 16-gigabyte model. It's available in the U.S. and several other markets.