(CNN) The US Secret Service says there is no system for tracking visitors to President Donald Trump's Florida resort at Mar-a-Lago, according to new court filings.

The revelation comes in response to a lawsuit filed by government watchdog groups who have sought visitor logs for the White House, Trump Tower in New York and Mar-a-Lago.

"(T)here is no system for keeping track of presidential visitors at Mar-a-Lago, as there is at the White House complex," wrote USSS Special Agent Kim Campbell in a court filing Wednesday. "Specifically, it was determined that there is no grouping, listing or set of records that would reflect presidential visitors to Mar-a-Lago."

Earlier this summer, a federal judge in New York ordered the Secret Service -- a component of the Department of Homeland Security -- to complete searches and turn over all records for Mar-a-Lago from January 20, 2017 to March 8, 2017.

The Secret Service turned over a list of only 22 names of foreign dignitaries and staffers related to Japanese Prime Minister Shinzo Abe's February trip to the Florida resort in response -- prompting Citizens for Responsibility and Ethics in Washington to go back into court asking the judge to hold the government in contempt for ignoring the court's order.

Campbell explained that "at the time of plaintiffs' request, the Secret Service's protective efforts at the Mar-a-lago location and the particular protective situation at the location were newly developed" in Wednesday's court filing.

In accompanying court documents, however, Justice Department attorneys defending the case make clear that other responsive records are being withheld.

"The government believes that presidential schedule information is not subject to FOIA," the attorneys wrote.

Noah Bookbinder, the executive director of CREW, said the government indicated that it would provide far more than the 22 names disclosed.

"We will be pressing the court for the full set of records that does exist," Bookbinder said. "If the government's statement is true, however, and there really are no records documenting the many people President Trump has met with at Mar-a-Lago, the government has just revealed that everyone from lobbyists to foreign agents can buy secret access to the President -- without accountability or even a simple record -- by paying his personal business. And that is terrifying."

Politico first reported the court filings.