"The Great, and even Legendary, Charlie Kirk, is dead. No one understood or had the Heart of the Youth in the United States of America better than Charlie," Trump wrote. "He was loved and admired by ALL, especially me, and now, he is no longer with us. Melania and my Sympathies go out to his beautiful wife Erika, and family. Charlie, we love you!"

Conservative activist Charlie Kirk was assassinated.

“With a high degree of certainty, we have him,” Trump said during a live interview on Fox News Channel on Friday morning.

The Wall Street Journal reported that additional security measures were put into place for the president's visit.

Extra security measures will be in place Thursday, Sept. 11 at Yankee Stadium, due to a scheduled visit by President Donald Trump.

The Yankees are planning to “recognize the victims and heroes’’ of Sept. 11, 2001 in ceremonies before the 7:05 p.m. game against the Detroit Tigers.

President Donald Trump and first lady Melania Trump are marking 24 years since the Sept. 11, 2001, attacks at a service at the Pentagon on Thursday.