SHANGHAI, Dec. 30 -- The first batch of vehicles produced by U.S. electric carmaker Tesla Inc.'s overseas plant in Shanghai was delivered Monday.

Fifteen Model 3 cars built in Shanghai were handed over to company employees at the Shanghai facility Monday. And deliveries to customers will start in January, company officials said at a ceremony to mark the delivery.

Tesla signed the agreement with the Shanghai municipal government in July 2018 to build the factory. In October 2018, the company was approved to use an 864,885-square-meter tract of land in Lingang Area, a high-end manufacturing park in the southeast harbor of Shanghai, for its Shanghai plant.

Tesla broke ground on Jan. 7 in Shanghai on its first overseas factory. The Shanghai plant is designed with an annual capacity of 500,000 electric cars.

The Shanghai mega factory now can produce 280 electric cars per day and will increase its production capacity, said Song Gang, the plant's manufacturing director.

The proportion of the car parts produced in China will also be increased from the current 30 percent to 100 percent at the end of 2020, Song added.