By Chang-Ran Kim and Soyoung Kim

NAGOYA/DETROIT (Reuters) - Toyota Motor's unprecedented recall of millions of vehicles with accelerator problems is taking a toll on sales and may force the world's largest automaker to cut 2010 sales forecasts.

U.S. auto sales for January due later on Tuesday are expected to show a sharp drop for Toyota after it pulled eight of its most popular models from showrooms last week following complaints over sticking accelerator pedals.

In the first public comment from an executive at Toyota's head office, the company's executive in charge of quality said he was expecting a bigger-than-usual impact from the recall.

"The sales forecast is something that we're extremely worried about," Executive Vice President Shinichi Sasaki he told a news conference in the central Japanese city of Nagoya.

"Already, I am hearing that sales have been affected somewhat in January," he said, adding the company will report its third-quarter earnings on Thursday.

On top of a separate recall for slipping floormats also linked to unintended acceleration, some 8.1 million Toyota vehicles are now being recalled, more than its total group sales last year.

Although Toyota says the occurance of problems is rare, public confidence is being shaken by coverage of the saga, including the harrowing details of the crash of a Lexus blamed on unexpected acceleration that killed an off-duty California state-trooper and three members of his family last year.

Sasaki, who appeared alone in front of more than 100 reporters, offered no deep bow of apology as has been seen at other 'scandal'-related media conferences in Japan.