Tesla Motors said today it would cut the third-quarter production target for its 2012 Model S all-electric sport sedan, according to a stock analyst who follows the company.

A report by Wunderlich Securities analyst Theodore O'Neill notes that Tesla is now saying it would probably only deliver 500 cars through the end of September, down from a previous target of 1,000.

It still expects to deliver about 5,000 cars by the end of 2012, meaning an average of 1,500 cars a month from October through December.

The delays were attributed to unspecified production execution issues.

Green Car Reports has asked Tesla for confirmation of the report, and will update this story if we receive further information.

[UPDATE: In response to a question asking for confirmation of the report, Tesla spokesperson Shanna Hendriks replied, "Tesla's plan has been and continues to be a focus on quality while ramping up production of Model S. This plan has not changed, and there have been no unexpected challenges or issues."

That translates to "no comment"; you may draw your own conclusions.]

Tesla delivered its first production Model S in late June, and is now slowly ramping up production of the pioneering electric luxury sedan.

It has said it expects to deliver 15,000 cars during 2013, once its assembly plant in Fremont, California, is up to a steady production rate.

The news caused Wunderlich to downgrade Tesla Motors stock and change its recommendation to Sell, setting a new target price of $28 per share--down from its previous target of $49.

Two other analysts, Jefferies Group and Maxim Group, left their Buy ratings for Tesla stock unchanged.

Tesla Motors [NSDQ:TSLA] stock declined steadily throughout yesterday; today the stock price climbed until about 1 pm and then began to fall.

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