TOKYO (AP) — Toyota said its quarterly profit slid 18.5 percent to 80.4 billion yen ($1 billion) on plunging sales caused by parts shortages from the tsunami disaster in northeastern Japan and warned it faces a new challenge from flooding in Thailand.

Toyota Motor Corp. declined Tuesday to give a forecast for the full financial year ending March 2012, citing uncertainties stemming from the Thai floods which have disrupted supplies of parts and prompted it to cut some car production.

Toyota, Japan's top automaker, said that vehicle sales plunged in the key markets of Japan and North America, but it was making up for some of the losses by strong sales in Asia, such as India and Indonesia.

Toyota's quarterly sales fell nearly 5 percent from a year earlier to 4.57 trillion yen ($58.7 billion).

All the Japanese automakers are suffering after the March 11 earthquake and tsunami in Japan damaged key parts suppliers. That meant they made and sold fewer cars than normal.

The Thai floods, which began in July and now threaten central Bangkok, are compounding the production damage. The country is the Southeast Asian base for several automakers. Toyota said production cuts in Japan, which began last month, will continue through Nov. 18.

Also battering Toyota is the surging yen.

Toyota, which makes the Prius hybrid, Camry sedan and Lexus luxury models, counted on the dollar costing 86 yen last year, but is now seeing it slip to 78 yen.

Toyota President Akio Toyoda said earlier this week that the strong yen was reaching levels "far beyond what is tolerable," threatening to make it necessary to move production out of Japan.

He asked that the government do more to prop up the dollar, stressing that manufacturing in Japan would be "destroyed," not just hollowed out, which is the common term to describe production moving out of Japan.

Toyota said the unfavorable exchange rate erased 80 billion yen ($1 billion) from its latest quarterly net income.

Toyota, which was the world's biggest automaker in annual vehicle sales last year, sank to No. 3 in the first half of this year, trailing U.S. rival General Motors Co. and Volkswagen AG of Germany.

Toyota had shown tremendous ability to bounce back after the March disaster, reaching pre-tsunami levels of global production in September, faster than its initial expectation of recovering by the end of this year.

But then the floods in Thailand struck and are expected to cost Toyota tens of thousands of vehicles in lost production.

For the first half spanning April 1 through Sept. 30, Toyota's profit nose-dived nearly 72 percent to 81.6 billion yen ($1 billion). It had eked out a tiny profit in the April-June first quarter. First-half sales fell 17 percent to 8.01 trillion yen ($103 billion).

Global sales for the six months totaled 3.03 million vehicles, down 18.5 percent from a year earlier as vehicle sales shrank in Japan, North America and Europe, according to Toyota.

"Toyota's biggest issue right now is production. They've had some bad luck this year with the tsunami and now the flooding in Thailand," said Chintan Talati, analyst at auto information site TrueCar.com.

"It looked as though they were about to get back on track and then got hit by this latest derailment," he said.

Talati said Toyota needs to keep bringing exciting models to attract new buyers. He believes Toyota has put the large recalls of 2009 and 2010 behind it, but still faces powerful competition not only from the U.S. automakers but also South Korea's Hyundai Motor Co., which have lured away Toyota fans.

Toyota shares lost 1.7 percent to 2,503 yen on the Tokyo Stock Exchange, shortly before earnings were announced.