Japanese auto giant Toyota Motor Corp. recalled more than half a million pickup and sport utility vehicles in the United States in the latest setback to its reputation for quality.

Toyota said in a statement it was recalling 533,000 Sequoia SUVs and Tundra pickup trucks in the United States, a key market where Japan's industry number one is putting the squeeze on ailing local automakers General Motors and Ford.

Including Canada and Germany, the total number of vehicles being recalled is 544,000, said a Toyota spokeswoman.

She said the defects had caused a total of 11 accidents and injured six people.

"There is a possibility that the front suspension lower ball joint may experience excessive wear and looseness, causing increased steering effort, reduced vehicle self centering and noise in the front suspension," Toyota said in a statement.

The recall covers certain 2004 through early 2007 model Sequoias and 2004 through late 2006 model Tundra vehicles which were also produced in the United States.

The potentially faulty parts will be replaced free of charge from mid-February. The company did not reveal the cost of the recall.

Toyota, which sold a record 2.54 million vehicles in the United States in 2006, announced several large recalls last year.

"While it is expanding the production in the United States, the company is suffering from a larger number of recalls since last year," said Tatsuya Mizuno, an auto analyst at Fitch Ratings.

"Markets have had concerns over the balance of Toyota's quality and business expansion."

Investors appeared unfazed by the recall, however. Toyota Motor shares closed unchanged at 7,980 yen while the Nikkei-225 index of leading shares fell 60.49 points or 0.35 percent to 17,310.44.

Toyota was last year instructed by Japan's transport ministry to improve its operations after local police alleged that the company knowingly failed to respond to a defect in a sports utility vehicle.

Toyota later submitted to the government a plan to improve its system for recalling defective vehicles following the rare official rebuke.

"The company said last year it would put more weight on its quality control, so the latest recall sounds disappointing," said Mizuno.

Toyota, the world's second largest automaker which is on course to overtake US giant General Motors, recalled over a million cars in Japan alone last year.

But the recalls have had little obvious effect on its sales or profits.

In November Toyota forecast the highest-ever annual operating profit for a Japanese firm helped by brisk sales of fuel efficient vehicles.

Toyota expects a 13 percent rise in net profit in the year to March to a record 1.55 trillion yen, on operating profit of 2.20 trillion yen and revenues of 23.2 trillion.

Toyota produced 9.04 million vehicles worldwide in 2006 and expects to lift output four percent in 2007 to 9.42 million vehicles.

General Motors this week reported preliminary global sales of 9.09 million vehicles for 2006, meaning it would also need to ramp up its production this year to hold on to the rank as the world's largest automaker by volume.