Shares of Tesla tumbled Tuesday following data showing a big drop in auto sales in China, adding to recent losses amid backlash to CEO Elon Musk's alliance with US President Donald Trump.

The electric auto maker sold 30,688 vehicles in China in February, down 49 percent from the year-ago period, according to data from the China Passenger Car Association.

Near 1840 GMT, Tesla shares were down 4.4 percent.

Tesla has lost more than one third of its market value since mid-December as Musk has deepened his association with the polarizing US leader.

Musk, who is the driving force behind the so-called Department of Government Efficiency, which is seeking to slash through the US budget, reportedly will attend Trump's address before Congress Tuesday night.

Musk has been excoriated among congressional Democrats for his role in cutting government jobs. He has also been criticized for endorsing far-right political figures in Germany and for making a hand gesture at Trump's inauguration that resembled a Nazi salute.