WASHINGTON — Two U.S. officials who helped negotiate an overhaul of North American trade rules have offered their services as private-sector advisers to future clients — making solicitations for post-government work while still on the federal payroll.

Jason Bernstein and Fred Fischer were key negotiators in U.S. Trade Representative Robert Lighthizer’s office responsible for the so-called rules-of-origin that dictate how much of a car must be made in North America to avoid tariffs under President Donald Trump’s renegotiated trade deal with Canada and Mexico.

They have reached out to companies in the auto industry to offer help implementing the U.S.-Mexico-Canada Agreement after they leave government service, according to documents reviewed by Bloomberg News and three people familiar with the communications who requested anonymity to discuss the private exchanges.

“As you know, Jason and I are looking to leave USTR, and we would like to assist companies directly with their USMCA implementation needs,” Fischer, the USTR’s senior automotive industry trade adviser, wrote last week in an email to an auto industry representative that was seen by Bloomberg News. The email referred the recipient to autovisory.com, which Fischer in the email called “our website,” for additional information.

The outreach came after the two told auto industry officials as early as March that they intended to leave their posts at the USTR and in the meantime had recused themselves from work related to the auto industry content rules within USMCA, according to people familiar with the communications.

When reached by phone Friday, Bernstein and Fischer declined to provide a comment and didn’t respond to subsequent email and voice messages seeking a response. A USTR spokesman didn’t reply to numerous telephone messages and emails.

The company’s website and its Instagram and Twitter accounts appeared to have been deactivated after Bloomberg News sought comment.

It is not uncommon for federal regulatory officials to cash in on their expertise after leaving the government by advising clients about the agencies where they once worked. But offering services as part of a private venture while on the government payroll would go a step further, according to ethics experts.

It couldn’t be learned if the men had asked for or received any clearance from the USTR ethics office to make the private solicitations. The office didn’t respond to numerous calls and emails sent after business hours seeking comment or confirmation the two had recused themselves from related work.

Virginia Canter, chief ethics counsel at the Citizens for Responsibility and Ethics in Washington, said that the conduct might be permissible under ethics laws if the officials recused themselves but it was still inappropriate.

“If you’re dealing with potential clients in the government workplace that would also have business before the government, it’s a problem,” she said.

Kedric Payne, general counsel and senior director for ethics at the Campaign Legal Center, said someone offering services while still working for the government could be breaching federal ethics requirements that prevent government employees from using their public positions for private gain.

“It just sounds like this is a straightforward example,” said Payne, who advised on executive branch ethics laws at the Energy Department.

Payne said even with recusals, promotion of a consulting business while still working for the agency should raise a red flag to ethics officials.

The USMCA is one of the main economic achievements of Trump’s first term and his administration has touted the stricter auto content rules as one of the most significant successes of its overhaul of the North American Free Trade Agreement.

Fischer wrote in emails to industry members that he and Bernstein, who is a senior trade adviser, would help companies conform to the new parts-sourcing rules in the USMCA. The two helped negotiate those complicated regulations, which many in the industry are trying to prepare for and are set to go into effect July 1.

The emails included a link to the website for Autovisory, which listed the two men as “founding partners” and says they “led the team” that developed the USMCA rules of origin regulations.

The website said it “helps companies comply with the new USMCA rules of origin” and advises on compliance with free trade agreements, government relations and strategy.

The site was freely available until Friday when Bloomberg News began making inquiries.

In a presentation attached to the emails to potential automotive clients and a trade association, the two men touted their more than 40 years of combined automotive and trade experience. They also noted their “extensive relationships within the U.S. Government, with the governments of Canada and Mexico, and throughout the automotive industry.”