SEATTLE — EBay has accused three Amazon managers of illegally conspiring to poach its sellers, escalating a monthslong feud between two of the country’s largest e-commerce companies.

In a lawsuit filed Wednesday in the United States District Court for the Northern District of California, eBay says the Amazon managers directed dozens of workers to illegally use eBay’s private messaging system to solicit sellers onto Amazon’s platform. The suit, which claims violations of the Racketeer Influenced and Corrupt Organizations Act, says the employees’ actions were “coordinated, targeted and designed to inflict harm on eBay.”

EBay first raised concerns that Amazon was poaching its sellers last fall in a lawsuit that has since moved to arbitration. In the new case, eBay says the outreach was not a few rogue employees but part of a larger effort within Amazon, with managers giving lower-lever employees lists of eBay sellers to target.

The anticompetitive behavior is being alleged at a touchy time for Amazon. Regulators and lawmakers in Washington are intensifying their scrutiny of the company’s market power, with some looking at its relationship with third-party sellers. In a recent hearing, for example, lawmakers pressed Amazon on whether the company used data from marketplace sellers to inform its own competing lines of private label products, which Amazon said it did not do.