Toyota Motor Corp <7203.T> by Thursday morning had not yet alerted U.S. safety regulators of a recall of Toyota and Lexus models for possible engine stalling while driving, a NHTSA official said.

Toyota officials in Tokyo earlier on Thursday said the world's top automaker was considering some kind of measure that may include the recall of 270,000 vehicles worldwide involving eight of its Toyota and Lexus models.

No accidents or injuries have been reported, Toyota said, related to the issue.

Since last September, Toyota has been plagued with a safety crisis that has led to the recall of more than 10 million vehicles globally, most for potential unintended acceleration. About 7.3 million vehicles have been recalled in the United States, the automaker's biggest market.

Toyota said that decisions by government regulators would determine if a recall was necessary for the eight models, including the high-end Lexus LS460 and Toyota Crown sedans.

The U.S. National Highway Traffic Safety Administration had not received any communication from Toyota regarding the issue as of early Thursday, according to a Department of Transportation spokeswoman. The DOT is the parent agency of the NHTSA.

Models involved have 4.6-liter and 3.6-liter engines, a Toyota spokeswoman in Tokyo said.

Some of these vehicles could have a problem with the valve spring in their engines that may cause idling trouble that could lead to engine failure, although no accidents have been reported, she said.

An autos analyst in Tokyo said investors were likely to shrug off news of a recall if it is limited and handled quickly by Toyota.

It's not as if there has been an accident caused by the possible defect, said Yoshihiko Tabei of Kazaka Securities. Investors are not worried as long as carmakers act quickly to address quality problems, he said, adding that focus in the auto sector is currently on labor disputes at parts suppliers in China.

Toyota shares shed 2.3 percent to 3,010 yen ($34.07), in line with the Topix subindex for the auto sector <.ITEQP.T> which fell 2.6 percent.

LEXUS RECALL LAST FRIDAY

Last Friday, Toyota told U.S. and Canadian safety regulators it was halting sales and recalling about 17,000 Lexus HS250h gasoline-electric hybrid sedans due to a potential fuel leak.

Toyota acted following a U.S. government crash test that showed fuel leaking after an HS250h was struck from the rear by a car traveling about 50 miles per hour.

Some 13,000 model-year 2010 HS250h vehicles were sold in the United States, and about 17,000 have been built to sell in the U.S. market, Toyota told its U.S. Lexus dealers in a letter last Friday.

Toyota's own crash test did not show the fuel leak problem. The automaker, in the letter to U.S. Lexus dealers, said it was trying to understand why the government tests showed the fuel leakage problem while the company's own crash tests did not.

The automaker told dealers it has not received any reports of injuries or accidents linked to the potential problem with the HS250h sedan.

(Reporting by Bernie Woodall in Detroit and Yumiko Nishitani in Tokyo; Editing by Maureen Bavdek)