Tesla Inc Chief Executive Officer Elon Musk said on Monday production of the $35,000 version of the electric carmaker's Model 3 will start this month, but would not reach "volume production" until mid-year.

"Gap in understanding is that $35k Model 3 production *starts* this month, but will not reach volume production until mid year. Extremely difficult to predict middle part of manufacturing S-curve," Musk said in response to a tweet https://twitter.com/elonmusk/status/1102669715095212032.

It was not immediately clear what Musk meant by "volume production." Tesla did not respond to a request for comment.

The launch of the $35,000 version, Tesla's cheapest model, last week comes at a crucial time for the company as some analysts had raised concerns that demand for the higher-priced versions of the Model 3 was beginning to dry up in the United States, especially after a federal tax credit was cut in half this year.

Tesla also said last week its global sales would now be online-only, in a bid to cut overhead costs.