China has never sought a trade surplus with the United States, a Chinese commerce official said on Thursday, as the world's two largest economies work to ease tension and develop rapport.

Sun Jiwen of the Ministry of Commerce told a press conference that, "China is willing to expand imports from the United States based on domestic demand."

Sun attributed the current trade surplus to differences in economic structure, industrial competitiveness and international division of labor.

The imbalance is easing as middle-income Chinese generate huge demand for imported products, a trend already shown in both US and Chinese official data.

The US trade deficit with China dropped 5.5 percent to around 347 billion US dollars in 2016, according to the US Department of Commerce. In February, the monthly figure declined 26 percent. Statistics from Chinese customs confirm the changes.

Sun hoped the United States would adjust its exports controls to create conditions to dissolve the deficit.

Although the surplus is registered in China's balance of trade, bilateral trade generates mutual benefits, he said. Analysts estimate that about 40 percent of the trade surplus is generated by US companies in China.

China has become the largest trade partner of the United States, while the latter is China's second largest. Bilateral trade stood at 520 billion US dollars in 2016, more that 200 times the level in 1979 when the countries established diplomatic ties.