President Donald Trump filed suit on Thursday against the US Internal Revenue Service (IRS), seeking $10 billion over alleged leaked tax returns he claims harmed his business.

The lawsuit -- filed by the president in his personal capacity along with his two eldest sons Eric and Donald Jr. and their family enterprise, The Trump Organization -- said the IRS and US Treasury Department "had a duty to safeguard and protect Plaintiffs' confidential tax returns."

Trump's tax returns were the focus of much speculation during his first term in office, after he broke with precedent and refused to release them as a candidate.

The tax documents were leaked to the press by Charles "Chaz" Littlejohn, a former IRS employee from May 2019 through September 2020, according to the lawsuit.

"Defendants have caused Plaintiffs reputational and financial harm, public embarrassment, unfairly tarnished their business reputations, portrayed them in a false light, and negatively affected President Trump, and the other Plaintiffs' public standing," read the lawsuit filed in Miami federal court.

Littlejohn in 2023 pleaded guilty to releasing Trump's tax returns and is currently serving a five-year sentence. 

The New York Times reported in September 2020 that Trump, who had repeatedly refused to make his tax returns public, paid only $750 in federal income tax in 2016 and 2017, and none at all for 10 of the previous 15 years.

This is not the first time the president has filed a legal claim against the federal government he oversees.

The New York Times reported Trump sought $230 million from the US Department of Justice over the investigations launched against him for mishandling classified documents and attempting to overturn the results of the 2020 election.