Motorola Inc. (MOT) Tuesday said quarterly earnings rose 34 percent, beating Wall Street expectations, as it regained global market share in wireless handsets amid robust sales of its most advanced phones.

But Motorola shares fell in after-hours trading as it said first-quarter earnings would be at the low end of analyst expectations.

Fourth-quarter earnings rose to $654 million, or 27 cents a share, compared with $489 million, or 20 cents a share, a year earlier.

Analysts had expected earnings of 24 centsr earlier, above Wall Street expectations, as the company benefited from an aggressive push of phones such as its high-end Razr V3 (search) during the key holiday selling season. Meanwhile, neck-and-neck competitors such as South Korea's Samsung Electronics Co. Ltd. (search) suffered from a weaker portfolio.

"They (Motorola) gained market share and were very profitable," said Charter Equity Research analyst Ed Snyder. "But the guidance for the next quarter isn't quite as strong."

Snyder said that may be because Nextel Communications Inc. (NXTL), a key Motorola customer, may be cutting back some business.

Motorola forecast first-quarter earnings of 17 cents to 20 cents a share, a range at the low end of Wall Street's average expectation of 20 cents a share, as tracked by Reuters Estimates.

First-quarter sales are seen at $7.5 billion to $7.9 billion, compared with $7.4 billion in last year's first quarter.

Schaumburg, Ill.-based Motorola said wireless handset shipments rose 42 percent to 31.8 million units in the fourth quarter ended Dec. 31, giving Motorola an estimated market share of 16.6 percent, compared with 13.4 percent at the end of the third quarter.

Motorola said it is now second worldwide in handset shipments, behind Finnish-based rival Nokia, retaking some of the share it had given up to Samsung.

Motorola's shares eased to $17.10 on Inet in after-hours trading Tuesday, compared with a close of $17.43 on the New York Stock Exchange (search).