SHANGHAI (BLOOMBERG) - Chinese electric vehicle maker Nio said a test car crashed from the third floor of its headquarters in Shanghai, killing two people.

The incident occurred on Wednesday (June 22) afternoon, leaving a Nio employee and a person from a partner company dead, the firm said in a statement on its official Weibo account, adding that the incident was "not caused by the car itself".

Nio said in a Thursday statement it is investigating the crash with police, and "can preliminarily confirm that it is an accident based on an analysis of the situation".

Videos circulating on Chinese social media showed a badly damaged vehicle on its side with chunks of concrete splayed across the ground beside it.

Rescuers in orange suits appear to be trying to get into the car at one point. It wasn't immediately clear what kind of test car was involved.

Nio has long branded itself as a premium car producer catering to middle class consumers.

Earlier this month it unveiled a five-seater SUV as it seeks to close the sales gap with local rivals Xpeng, Li Auto and others.

Nio's US-listed shares fluctuated on Thursday. They're down more than 28 per cent this year.