Tesla achieved one of the company’s biggest milestones of the year when, on Monday, the electric carmaker confirmed it delivered the first Model 3 cars built at its Gigafactory in Shanghai.

In what was a symbolic move, Tesla delivered 15 Model 3s to company employees who had worked on the cars at the company’s Chinese production facility. Tesla posted on Twitter to mark the occasion, saying the deliveries are “only just the beginning” for the company’s production efforts in China.

Tesla Chief Executive Elon Musk also went on to Twitter himself to praise what he called “Amazing work by (the) Tesla China team!”

The Chinese-made Teslas were delivered less than a year after Tesla broke ground on its Shanghai Gigafactory in January. Musk has said that the factory will soon be producing 1,000 cars a week, and will be capable of building up to 500,000 vehicles a year once it reaches full production capacity.

China is seen as a key market for Tesla’s international expansion efforts. Tesla has been exporting cars built in the United States to China, and with sales of $669 million in third quarter of 2019, the country has already become Tesla’s single-largest national source of revenue after the U.S.