President Donald Trump’s first four visits to his Mar-a-Lago resort after Inauguration Day cost American taxpayers $13.6 million, according to a report released Tuesday by the US Government Accountability Office.

According to the report, some $10.6 million was spent between February and March 2017 on “operating costs of government aircraft and boats” and $3 million went toward “temporary duty costs of government personnel supporting the President’s travel, including transportation, lodging, and meals and incidental expenses.” Some $60,000 of that was paid directly to Trump’s Florida club.

The Defense Department and the Department of Homeland Security incurred the majority of the costs, and the report says the estimate excludes certain classified cost information.

The report also analyzed the costs of three international trips by the President’s sons Donald Trump Jr. and Eric Trump that took place in January and February 2017.

The report says protective details for the President’s sons and their spouses on the trips to Uruguay, the Dominican Republic and the United Arab Emirates cost about $396,000. Commercial aircraft was used for these trips and no military aircraft supported their travel, the report says.

The GAO also determined that the Defense Department and the Secret Service did not regularly report the costs of protecting the President to Congress. The office recommended that the agencies regularly submit the cost reports, which are “required under the Presidential Protection Assistance Act of 1976.”

Both DHS, of which the Secret Service is a part, and the Defense Department “concurred with GAO’s recommendations,” the report continues.

CNN has reached out to the White House for comment.

Congressional Democrats requested the GAO analysis in 2018 following Trump’s visits to Mar-a-Lago during the first months of his presidency.

They called the report’s findings “alarming” and said they’d keep investigating the spending.

“This alarming report captures a snapshot of the tens of millions of dollars President Trump spends to travel to his Palm Beach resort — all at taxpayer expense — including government funds that are paid directly to a business in which the president himself has a financial interest,” Sens. Gary Peters of Michigan and Dianne Feinstein of California and Rep. Elijah Cummings of Maryland said Tuesday in a joint statement.

“This is part of a troubling pattern of wasteful spending and serious abuse of tax dollars by the administration. We will keep investigating this issue to ensure taxpayer dollars are being used effectively and appropriately,” the statement continued.

CNN previously reported that Mar-a-Lago had collected at least $63,700 in taxpayer dollars from the Secret Service between February and April 2017. Redactions to expense forms obtained by CNN made the purpose of those charges unclear. Experts told CNN the bills could be for rooms for the President’s detail, space leased for communications equipment or other purposes.