Former President Donald Trump pleaded not guilty in a federal courthouse in Washington, DC, on Thursday to criminal charges related to special counsel Jack Smith's investigation into attempts to overturn the 2020 presidential election.

"This is a very sad day for America," Trump said while giving brief remarks before boarding his plane to return to New Jersey, calling the recent indictment "a persecution of a political opponent."

The four counts against Trump are conspiracy to defraud the United States; conspiracy to obstruct an official proceeding; obstruction of and attempt to obstruct an official proceeding; and conspiracy against rights.

This is the third time Trump has been criminally indicted. Smith charged Trump in a classified documents probe in June, and a Manhattan grand jury charged the former president for business fraud in March. Trump pleaded not guilty in both of those cases.

Trump, who is running for president in 2024, has repeatedly denied wrongdoing and accused Democrats of targeting him politically.

Trump waves from inside his SUV on his way to court in Washington, DC, on Thursday.
Trump waves from inside his SUV on his way to court in Washington, DC, on Thursday.
Brendan Smialowski/AFP/Getty Images
Alina Habba, one of Trump's lawyers, speaks to the media outside the courthouse.
Alina Habba, one of Trump's lawyers, speaks to the media outside the courthouse.
Alex Brandon/AP
Trump's motorcade arrives at the E. Barrett Prettyman US Courthouse in Washington, DC.
Trump's motorcade arrives at the E. Barrett Prettyman US Courthouse in Washington, DC.
Rebecca Wright/CNN
Members of the media and bystanders try to catch a glimpse of Trump's motorcade.
Members of the media and bystanders try to catch a glimpse of Trump's motorcade.
Chip Somodevilla/Getty Images
Trump lands in Arlington, Virginia, on Thursday.
Trump lands in Arlington, Virginia, on Thursday.
Alex Brandon/AP
Trump's plane passes the Washington Monument.
Trump's plane passes the Washington Monument.
Jess Rapfogel/AP
Trump supporters hold "Blacks For Trump" signs outside the federal court in Washington, DC, on Thursday.
Trump supporters hold "Blacks For Trump" signs outside the federal court in Washington, DC, on Thursday.
Nathan Howard/Bloomberg/Getty Images
Buttons are on display outside the courthouse.
Buttons are on display outside the courthouse.
Jacquelyn Martin/AP
Tourists atop a double-decker tour bus pass by assembled reporters, law enforcement officers and demonstrators as they wait for Trump to arrive at the federal courthouse.
Tourists atop a double-decker tour bus pass by assembled reporters, law enforcement officers and demonstrators as they wait for Trump to arrive at the federal courthouse.
Jonathan Ernst/Reuters
A reporter with ABC7 prepares for a standup outside the courthouse on Thursday.
A reporter with ABC7 prepares for a standup outside the courthouse on Thursday.
Rebecca Wright/CNN
Demonstrators gather outside the courthouse.
Demonstrators gather outside the courthouse.
Kevin Wurm/Reuters
Law enforcement officers patrol outside the courthouse.
Law enforcement officers patrol outside the courthouse.
Nathan Howard/Bloomberg/Getty Images
Daniel Demoura, a Trump supporter from Boston, waves a "Trump 2024" flag outside the courthouse.
Daniel Demoura, a Trump supporter from Boston, waves a "Trump 2024" flag outside the courthouse.
Rebecca Wright/CNN
Suzzanne Monk wears a ribbon in support of the people who were arrested after participating in <a href="index.php?page=&url=https%3A%2F%2Fwww.cnn.com%2F2022%2F01%2F03%2Fpolitics%2Fgallery%2Fjanuary-6-capitol-insurrection%2Findex.htmlhttps%3A%2F%2Fwww.cnn.com%2F2022%2F01%2F03%2Fpolitics%2Fgallery%2Fjanuary-6-capitol-insurrection%2Findex.html" target="_blank">the January 6 Capitol riot</a>.
Suzzanne Monk wears a ribbon in support of the people who were arrested after participating in the January 6 Capitol riot.
Jacquelyn Martin/AP
A US Marshal's K-9 patrols outside the courthouse.
A US Marshal's K-9 patrols outside the courthouse.
Brendan Smialowski/AFP/Getty Images
People with the progressive organization Herndon Reston Indivisible demonstrate outside the courthouse.
People with the progressive organization Herndon Reston Indivisible demonstrate outside the courthouse.
Rebecca Wright/CNN
Buttons adorn a person's backpack outside the courthouse.
Buttons adorn a person's backpack outside the courthouse.
Rebecca Wright/CNN
Workers install security fencing along the street outside the courthouse Thursday.
Workers install security fencing along the street outside the courthouse Thursday.
Kent Nishimura/Getty Images
Members of the media camped out overnight for a spot in the courtroom.
Members of the media camped out overnight for a spot in the courtroom.
Stefani Reynolds/AFP/Getty Images
Pedestrians walk by a message written in chalk on the sidewalk outside the courthouse Wednesday, August 2.
Pedestrians walk by a message written in chalk on the sidewalk outside the courthouse Wednesday, August 2.
Drew Angerer/Getty Images
Workers set up security barricades outside the US Capitol on Wednesday.
Workers set up security barricades outside the US Capitol on Wednesday.
Stefani Reynolds/AFP/Getty Images
The indictment against Trump includes charges related to his efforts to overturn the results of the 2020 presidential election.
The indictment against Trump includes charges related to his efforts to overturn the results of the 2020 presidential election.
Rebecca Wright/CNN
Special Counsel Jack Smith announces the indictment during a press conference in Washington, DC, on Tuesday, August 1.
Special Counsel Jack Smith announces the indictment during a press conference in Washington, DC, on Tuesday, August 1.
Ricky Carioti/The Washington Post/Getty Images