Tesla says its annual revenue has fallen for the first time as the electric vehicle (EV) maker shifts it focus to artificial intelligence (AI) and robotics. Tesla also announced plans to end production of its Model S and Model X vehicles. In January, China's BYD overtook Tesla as the world's largest EV maker, while Musk's involvement in politics in the US and abroad has been controversial. It comes after Musk's entry into politics, including a high-profile cost-cutting role in the administration of US President Donald Trump. "The Model S and Model X have been low-volume vehicles for Tesla for a while now," said Jessica Caldwell, Head of Insights at Edmunds.