"We were able to double the weekly Model 3 production rate during the quarter by rapidly addressing production and supply chain bottlenecks, including several short factory shutdowns to upgrade equipment," Tesla said in the filing.
Auto industry blogs -- citing an unverified memo -- had reported on Tuesday that production of the Model 3 passed the 2,000 per week production rate.
Meanwhile, Elon Musk, in a testy Twitter exchange, said he is "back to sleeping at the factory" while trying to fix production delays with the Model 3. It's a move reminiscent of Tesla's last vehicle launch -- the Model X -- when Musk famously kept a sleeping bag near the production line so he could immediately address any hiccups.
"Car biz is hell," Musk said.
Taking over production
The Twitter exchange, with a reporter at The Information, a tech and business news site, followed a story by the outlet that Musk had taken over Model 3 production from Tesla's head of engineering, Doug Field. For the last year, Field has managed engineering of both the vehicle and its production. Musk said Field had originally been tasked with both jobs to ensure Tesla doesn't design cars that are "crazy hard to build," but now that Tesla was back in the thick of production, "it's better to divide and conquer."
Musk had vowed he would be making 2,500 cars a week by the end of the first quarter -- a target that was already scaled back from a prior forecast of 5,000 a week by the end of 2017.
Tesla has built up a die-hard fan base, with some half million people putting down $1,000 reservations for the Model 3 since it was unveiled two years ago. But the company is still trying to prove that it has what it takes to be a true mass-production company.
When Tesla rolled out the Model X in late 2015, it was years behind schedule, and production was marred by problems with its complicated falcon wing doors, custom mono-post rear seats and other unique new high-tech features. Musk told investors in 2016 that he kept a sleeping bag on hand and moved his desk to wherever the factory problems were most troublesome.
It's not clear where Tesla's current bottlenecks reside.
During a first-quarter earnings call, Musk said the primary holdup was with robots at the company's battery Gigafactory. A new production line had been built for it at Tesla's Grohmann Automation labs in Germany and was scheduled to be installed last month.
If Musk is instead camping out at the carmaker's Fremont, Calif., factory, that would suggest his attention has shifted away from the batteries to car assembly.
Tesla wants to double production in the next three months, to 5,000 cars a week. Fremont is where that will, or won't, happen. Even if Tesla is able to reach its first-quarter production target, it's not clear whether the company will be able to sustain and build off of it. According to Musk's latest posts on Twitter, the company hasn't emerged from production hell just yet.
Reuters and Bloomberg contributed to this report.