General Motors North America president Gary Cowger expects US vehicle sales for September to be similar to last year, when sales fell to an annual rate of 15.9 million, excluding heavy trucks, due to the September 11 terrorist attacks, Reuters reported.

According to Reuters, other automotive executives and analysts have also said that US sales for September would drop sharply from July's strong rate of 18.7 million vehicles, the highest level since the record results in October last year.

Reuters said that marketing information services firm JD Power and Associates forecast last week that US vehicle sales for September this year would fall to an annual rate of 15.9 million.

Both last October's and July's sales results were boosted by zero percent financing offers from automakers, Reuters said.

Cowger told Reuters that despite the drop in September sales, the interest free financing continue to work and he sees no end to consumer incentives.

"Right now, zero percent is running very strong," he said. "Despite what everybody says, I don't see any let-up on the incentive front," Cowger said, according to Reuters.