(Reuters) - Tesla will give a one-month trial of its driver-assist technology Full Self-Driving (FSD) to existing and new customers in the United States, according to Tesla CEO Elon Musk and the company's website.

Musk also is requiring Tesla staff to give demonstrations of FSD to new buyers and owners of serviced vehicles, according to two emails verified by a Tesla source.

The move comes as Tesla sales and margins are under pressure because of price competition and softening demand. FSD is an add-on priced at $12,000, enabling vehicles to navigate city streets.

Tesla calls its driver-assisting systems Autopilot and Full Self-Driving, but says the features do not make its vehicles autonomous and require active driver supervision. Musk has for years missed his promise of achieving full autonomy, and Tesla's driver assistant software is under regulatory scrutiny over safety and marketing.

"All US cars that are capable of FSD will be enabled for a one month trial this week," Tesla CEO Elon Musk confirmed in a post on social media platform X on Monday.

The trial has been offered on new sales of Tesla models X, S, and Y, according to Tesla's website.

Tesla's margins have been hurt by a price war with rivals that started more than a year ago. In January, Tesla warned of "notably lower" sales growth this year as it focuses on the production of its next-generation EV, which is code-named "Redwood."

The company is also dealing with a rise in regulatory scrutiny of its self-driving systems and other areas in the United States and in some European countries. In December, Tesla recalled nearly all of its 2 million vehicles on U.S. roads to install new safeguards.