LOS ANGELES, USA: Consumer Reports will not recommend Apple's iPhone 4 to buyers after testing and confirming the device's well-publicized wireless signal and reception glitches, adding that AT&T was not necessarily the main culprit.

The influential nonprofit organization, which publishes guides on everything from cars to TVs, said in a report released on Monday that it tested three iPhone 4s and other phones -- including the iPhone 3GS and Palm Pre -- and found none had the signal-loss problems of Apple's latest, highly touted iPhone.

The report marked the latest blow for a device that sold 1.7 million units in three days, but which has been plagued by complaints about poor reception. Many of the complaints involve a wraparound antenna that is said to reduce signal strength if touched in a certain way.

The company has been sued by iPhone customers in at least three complaints related to antenna problems.

"When your finger or hand touches a spot on the phone's lower left side -- an easy thing, especially for lefties -- the signal can significantly degrade enough to cause you to lose your connection altogether if you're in an area with a weak signal," contributor Mike Gikas said in a report on the group's website.

"Due to this problem, we can't recommend the iPhone 4."

Apple representatives were not immediately available for comment.

The signal can degrade enough to drop a call altogether when a finger or hand touches a spot on the iPhone 4's lower left side, the consumer products testing company said. It recommended covering the gap in the wraparound antenna with duct tape or some other non-conductive material.

The organization also said its tests indicated that AT&T's network was not the chief culprit in the iPhone 4's much talked-about reception problems.

Apple has said almost any cellphone will suffer a loss of signal if held in certain ways. It said later it had discovered a software glitch that overstates signal strength, though it did not directly address concerns about the antenna with that admission.

On the flip side, Consumer Reports said the iPhone scored high on other testing grounds such as battery life, sharp display and high-quality video camera.

"But Apple needs to come out with a permanent -- and free -- fix to the antenna problem before we can recommend the iPhone4," said Gikas in his blog post on ConsumerReports.org.

Apple shares were down less than 1 per cent at $257.46 on Monday afternoon on the Nasdaq.