Elon Musk’s Twitter profile is seen on a smartphone placed on printed Twitter logos in this picture illustration taken April 28, 2022.

Dado Ruvic | Reuters

Sen. Ed Markey chastised Twitter’s owner Elon Musk Sunday for his response to Markey’s request for answers about the platform’s new verification and impersonation policies.

After a Washington Post reporter successfully set up a fake verified account pretending to be the Massachusetts Democrat, Markey shared a letter to Musk on Twitter Friday asking him to “explain how this happened and how to prevent it from happening again.”

In response, Musk wrote back to Markey in a tweet Sunday and said, “Perhaps it is because your real account sounds like a parody?”

Markey did not appear to appreciate Musk’s response.

“One of your companies is under an FTC consent decree. Auto safety watchdog NHTSA is investigating another for killing people. And you’re spending your time picking fights online. Fix your companies. Or Congress will,” Markey wrote in a tweet Sunday.

Twitter appeared to have paused the $7.99 a month Twitter Blue verification program shortly after the Post ran its test as impersonations of celebrities and brands proliferated across the platform.

But prior to the pause, the Post was able to set up a Twitter handle called “@realEdMarkey” using “a spare iPhone, a credit card and a little creativity.” The account received a blue verified checkmark, even though Markey already has two legitimate verified accounts.

The blue check is supposed to be a feature of the paid Twitter Blue, but the Post reporter found that Twitter said the fake Markey account was verified “because it’s notable in government, news, entertainment, or another designated category.”

Twitter has recently lost key privacy and content moderation executives.

“Safeguards such as Twitter’s blue checkmark once allowed users to be smart, critical consumers of news and information in Twitter’s global town square,” Markey wrote in his letter to Musk. “But your Twitter takeover, rapid and haphazard imposition of platform changes, removal of safeguards against disinformation, and firing of large numbers of Twitter employees have accelerated Twitter’s descent into the Wild West of social media.”

Markey asked Musk to respond to his questions in writing by Nov. 25.

The exchange between Musk and Markey on Twitter is not the first time the pair has gone head-to-head.

Musk is also the CEO of the automaker Tesla, and Tesla’s driver assistance systems are branded Autopilot and Full Self Driving in the U.S. During a series of Tesla crashes in August 2021, Markey and Sen. Richard Blumenthal (D-Conn.) expressed “serious concerns” about the way the company advertises these technologies. They asked the Federal Trade Commission to launch an investigation.

The senators also called on the National Highway Traffic Safety Administration in June to take “aggressive investigative and enforcement action on vehicles with automated driving systems (ADS) and advanced driver assistance systems (ADAS)” after the administration released data showing more than 500 crashes in vehicles with these technologies.

— CNBC’s Lauren Feiner and Laura Kolodny contributed to this report.