SAN FRANCISCO, UNITED STATES - Apple Inc has called a surprise press conference for Friday to talk about the iPhone 4, as the company continues to deal with fallout from reported reception problems on its popular smartphone.

Apple spokesman Steve Dowling said late on Wednesday the company would hold the event at 10 a.m. on Friday at its headquarters in Cupertino, California.

He declined to provide further details, or to say whether the event will address the signal-strength problems that some people have reported having with the iPhone 4 when the device is held in a certain way.

Apple has faced mounting criticism from analysts and consumers over its handling of complaints about the reception issues on the newest iPhone, which was launched last month.

Analysts say Apple has created a public relations headache for itself by appearing to dismiss or ignore the problem, allowing a minor issue to be turned into headline news.

Although most analysts believe a recall of the device is unlikely, a growing chorus have urged Apple to resolve the matter, perhaps by offering free iPhone cases, which appear to solve the problem.

The iPhone 4 has been an unqualified hit with consumers, and sales have so far been unaffected by the controversy, analysts say. Apple sold 1.7 million units in its first three days to become the fastest selling device in the company's history.

But scattered reports cropped up early on from users who complained about decreased signal strength when they touched certain parts of the phone.

The company has been sued by several consumers over the matter. Still, the problem does not appear to be widespread.

Earlier this month, Apple issued a statement, saying the problem was caused by a software glitch that overstates network signal strength. But some found that explanation wanting.

Many who follow the company believe the problem is with the hardware itself. A steel band runs along the outside of the iPhone 4 and acts as the antenna.

The influential publication Consumer Reports said on Monday it could not recommend the iPhone 4 to buyers because of problems with its signal-strength. It has called on Apple to provide a free fix to iPhone 4 buyers.

Shares of Apple closed up 0.4 percent at $252.73 on Nasdaq on Wednesday.