TOKYO -- Toyota Motor Corp. predicts its North American car and truck sales will be 682,000 in the January-March quarter, an 18.4 percent jump from a year earlier.

The rise will come on the heels of an 11.6 percent gain in the October-December quarter, to 643,000. The back-to-back increases show strong demand for Toyota vehicles in North America, even as General Motors and Ford Motor Co. struggle to maintain their sales to customers beyond fleets.

Toyota did not give separate forecasts for the United States and Canada.

Some Japanese carmakers, including Honda Motor Co. and Nissan Motor Co., have trimmed their light-truck output in North America amid signs of softening demand. Not Toyota.

"As of today, our North American plants don't require any production change," says Takeshi Suzuki, Toyota's senior managing director in charge of the finance and accounting group. Citing Toyota's full-sized pickup, he added, the "Tundra hasn't shown a relative decrease in sales."

The sales forecast came as Toyota said the company as a whole racked up strong profits in the quarter that ended Dec. 31, 2005, thanks to a favorable exchange rate and higher sales in North America.

Operating profits rose 14.0 percent to 482.21 billion yen, or $4.08 billion, in the three months to Dec. 31 compared with the year-earlier period. Net income rose 34.1 percent to $3.37 billion.

Revenues rose 14.8 percent to $45.17 billion as unit sales grew 7.6 percent to 1,980,000. The sales growth came in North America, Asia, Africa and Central and South America. Sales fell in Japan and Europe.

Operating profits jumped by $502.2 million compared with a year earlier. Among the major contributors, currency gains added $1.10 billion, and higher volume added another $508.2 million. However, increased expenses, including costs to raise output to meet demand, and accounting changes subtracted $1.12 billion from profits.

North American operating profits were flat in the quarter at $1.08 billion, even though unit sales jumped 11.6 percent to 643,000. The North American tally excludes profits on vehicles exported from Japan, which are booked as Japanese profits.

Yen amounts were converted at the rate prevailing on Dec. 31, 2005.