Tesla has seen its profits slide even as it reported record quarterly revenue after US buyers rushed to secure a key tax credit on electric car purchases before it ended last month.

The firm said revenue for the three months to the end of September hit a record $28bn (£21bn), up 12% from the same time last year.

But the company’s profits dropped by 37% for the same period, partly due to extra costs linked to tariffs and research.

The results come ahead of a vote by shareholders in November on a new pay package for chief executive Elon Musk that could be worth as much as $1tn (£749m).

Tesla shares were down by around 3.7% in extended trading after the results were announced.

The company’s roughly $1.4tn stock market valuation has been driven in recent months by investor confidence that Musk can deliver on his ambitions to transform Tesla into a global leader in artificial intelligence (AI) and robotics.

But sales of vehicles currently remain its main source of income while those new products are being developed.

Tesla, like other car makers around the world, is facing tough competition from Chinese rivals such as China’s BYD.