Tesla is working on its semi-truck and progress is being made, says CEO Elon Musk, but the company’s focus is currently on the Model 3. Musk announced last year that Tesla would move into the semi-truck business.

On Twitter, he was asked about the Tesla Semi. He noted progress is being made, though the Model 3 is an “overwhelming priority.”

A semi is among a few future electric vehicles discussed in Tesla’s Master Plan Part 2 from 2016. That plan also mentioned a minibus and a pickup truck. Tesla currently has a sedan and a crossover SUV.