U.S. Markets closed

Watch: Trump addresses 9/11 service at Flight 93 memorial in Pennsylvania

Kevin Breuninger

[The stream is slated to start at 10:30 a.m. ET. Please refresh the page if you do not see a player above at that time.]

President Donald Trump is set to give remarks Tuesday at a ceremony in Shanksville, Pennsylvania, commemorating the September 11, 2001, terrorist attacks.

First lady Melania Trump will also participate in the ceremony, the White House told NBC News.

Shanksville became associated with 9/11 after passengers revolted against terrorists who had hijacked United Airlines Flight 93, crashing the plane into the small town.

On the morning of the 17th anniversary of the attacks on the Pentagon in Arlington, Virginia, and the World Trade Center in New York City, Trump sent tweets railing against his own Justice Department and special counsel Robert Mueller 's Russia investigation.

Trump tweet Russia 1

Trump tweet Russia 2

The president also praised his personal lawyer, former New York Mayor Rudy Giuliani , for his "leadership, bravery and skill" in responding to the attacks.

Trump tweet Rudy

Trump also shared a message from his social media director, Dan Scavino , which shows Trump signing a proclamation for "Patriot Day 2018" honoring the nearly 3,000 people killed in the attacks, as well as the first responders who worked to save lives.

"The noble sacrifices of these true patriots are forged into the great history of America," the proclamation says.

The document also calls on government agencies to display flags at half-staff.

More From CNBC