In a letter to Rep. Elijah Cummings, top Democrat on the House of Representatives Committee on Oversight and Government Reform, the Government Accountability Office said Monday it would begin the inquiry into Trump's Mar-a-Lago visits "shortly," after Cummings and Democratic Sens. Elizabeth Warren, Sheldon Whitehouse and Tom Udall requested the probe.
The scope of the inquiry will include how classified information is protected at the private club, what type of security measures are taken to screen "individuals with access to Mar-a-Lago" and what measures are in place "to ensure charges for travel-related expenses in connection with providing protection for presidential trips to Mar-a-Lago are fair and reasonable."
The government watchdog will also look into whether Trump is keeping his promise to take any profits made at his hotels from foreign governments and transfer them to the US Treasury. Trump's lawyer promised at a news conference in January that, in an effort to avoid conflict of interest, he wouldn't keep such profits.
"He is going to voluntarily donate all profits from foreign government payments made to his hotels to the United States Treasury," said Sheri Dillon, Trump's tax attorney. "This way it is the American people who will profit."
CNN has reached out to the White House for comment.
The watchdog inquiry comes as Democrats raise questions about the costs and security questions that comes with Trump's frequent trips to Mar-a-Lago, a private club he has owned since 1985 and a home he has visited for six weekends since becoming president in January.
Variations in each trip make it difficult to estimate how much it actually costs for Trump to spend weekends in Florida. But a 2016 GAO report about a four-day trip President Barack Obama took to Florida in 2013 found the total cost to the Secret Service and Coast Guard was $3.6 million.
Security concerns were heightened in February when Trump and Japanese Prime Minister Shinzo Abe appeared to be strategizing over how to respond to a North Korean missile test while having dinner in plain sight on Mar-a-Lago's candlelit patio.
"We have accepted this request to review security and site-related travel expenses related to the President's stays outside the White House at Mar-a-Lago," Chuck Young, managing director for public affairs at GAO, told CNN Tuesday.
Young said there is no time frame yet for their review, but that they will first work to "determine the full scope of what we will cover and the methodology to be used."
"Until that is complete, we don't have any projected dates," Young said. "We handled it as we do all requests, from either side of the aisle, using our standard protocols."
The GAO inquiry comes as Democratic Sens. Udall, Whitehouse, Jack Reed and Tom Carper introduced legislation in the Senate that would require the White House to publish a list of people who visit Mar-a-Lago. Rep. Mike Quigley, an Illinois Democrat, introduced the same legislation in the House.
The Making Access Records Available to Lead American Government Openness Act -- or Mar-a-Lago Act, for short -- would treat the Florida club like the White House, where a log of visitors is required.
The act would allow for very few exceptions, including visits that would spark security concerns and "purely personal" visitors.