The Pre smartphone, seen here with a wireless charger, has been a surprise success for Palm Inc., which once was a forerunner in the smartphone market before Apple and Research In Motion overtook it in sales. (Jae C. Hong/Associated Press)

Apple Inc. has shut down one of the most compelling features on Palm Inc.'s rival Pre smartphone, crippling the Pre's ability to act like an iPod.

Users of the recently released Pre had been able to put music on it by using Apple's free iTunes software — a unique twist for a device not made by Apple. But Apple updated iTunes on Wednesday to block this feature.

Apple spokesman Tom Neumayr said the update "disables devices falsely pretending to be iPods, including the Palm Pre."

Palm spokeswoman Leslie Letts said Apple's move is a "direct blow to their users, who will be deprived of a seamless synchronization experience." For a workaround, she noted, Pre owners can stick to the older version of iTunes, move music from computers to a Pre with a USB cable or consider third-party music applications.

Former Apple exec now leads Palm

The iTunes software smackdown is the latest example of tensions brewing between Apple and Palm, which since June has been led by the former executive behind the iPod, Jon Rubinstein. Rubinstein became Palm's executive chairman in October 2007.

The $200 US Pre includes a "multi-touch" screen like Apple's iPhone, letting users do things like pinch photos to zoom in and out. Apple was granted a patent in January related to certain multi-touch functions, though the effects on Palm are unclear.

Avian Securities analyst Matthew Thornton said Apple's move to quash the Pre's iTunes function could turn off some people looking to buy the Pre, since they might have considered the device as a way to consolidate their music player and cellphone.

Still, "it's not like 10 out of every 10 people who buy a Pre are going to use the device for their MP3 player," he said.