Former President Donald Trump expressed gratitude to law enforcement for their "exceptional" response to what the FBI has labeled as an assassination attempt at Trump's Palm Beach, Florida, golf course on Sunday.

"I want to thank everyone for their concern and well wishes - It was certainly an unusual day!," Trump stated in a post on Truth Social.

"Of utmost importance, I extend my gratitude to the U.S. Secret Service, Sheriff Ric Bradshaw and his Office of courageous and dedicated Patriots, and, all Law Enforcement, for the exceptional work carried out today at Trump International in safeguarding me, as the 45th President of the United States, and the Republican Nominee in the upcoming Presidential Election, SAFE."

"THE WORK DONE WAS ABSOLUTELY OUTSTANDING. I AM VERY PROUD TO BE AN AMERICAN!" he wrote.

Secret Service agents accompanying Trump fired at a man armed with an AK-47-style rifle on or near the Trump International golf course on Sunday. The incident occurred roughly two months after Trump was shot in the ear at a campaign rally in Butler, Pennsylvania.

The FBI is investigating the incident as an "attempted assassination." Multiple law enforcement sources told
that 58-year-old Ryan Wesley Routh was detained by Florida authorities in relation to the incident.

Palm Beach County Sheriff Ric Bradshaw disclosed at a press conference on Sunday afternoon that the assailant was positioned between 300 and 500 yards away from Trump when he was detected. Secret Service agents discharged four to six rounds at him before he discarded his weapon and escaped the scene in a vehicle. Eyewitnesses provided the license plate number to authorities, leading to the suspect's apprehension and detention.

It was not clear if the suspect was aiming his gun at the former president. Agents fired at the suspect after spotting his rifle through the fence line, multiple sources told
.

Sources indicated that three spent shell casings, believed to be associated with the suspect's AK-47, were found at the location. However, investigators are still assessing whether the suspect discharged his firearm. The rifle and two backpacks containing a GoPro camera and ceramic tiles were recovered from the scene, Bradshaw stated.

Sources reported that Trump was promptly escorted to a secure area on the golf course premises following the gunfire.

Authorities are now probing Routh's background. The detainee is believed to have ties to North Carolina and Hawaii, sources said. Sources told
that the FBI is conducting an extensive investigation into Routh's social media activity, travel and any criminal record. Friends, family and associates are also being sought for interviews.

Sources knowledgeable about the investigation have stated that authorities are exploring a possible link between Routh's actions and any dissatisfaction he may have held regarding Trump's stance on Ukraine.

Authorities are expected to file charges relating to the incident in the coming days, sources told
.

President Joe Biden and Vice President Kamala Harris both denounced the attempted assassination.

"As I've stated before, there's no room for political violence or any violence in our nation. I've instructed my team to ensure the Secret Service has all the resources, capabilities and protection needed to keep the former President safe," Biden stated.

Harris expressed her "thankfulness" for Trump's safety and expressed being "deeply troubled by the potential assassination attempt."

"As we gather the information, I want to be clear: I denounce political violence. We all have a responsibility to ensure that this incident does not escalate into further violence," Harris stated.

' Lalee Ibassa, Katherine Faulders, Aaron Katersky, Soo Rin Kim, Michelle Stoddart, Pierre Thomas, Rachel Scott, Jack Date, Leah Sarnoff and Kelsey Walsh contributed to this report.