Donald Trump thanks “outstanding” law enforcement after apparent assassination attempt

Former President Donald Trump thanked law enforcement for their “incredible” response to what the FBI called an assassination attempt on Trump's golf course in Palm Beach, Florida, on Sunday.

“I want to thank everyone for their concern and well wishes – it has certainly been an interesting day!” Trump said in a post on Truth Social.

“Most importantly, I want to thank the U.S. Secret Service, Sheriff Ric Bradshaw and his office of brave and dedicated patriots, and all law enforcement for the incredible job they did today at Trump International to keep me SAFE as the 45th President of the United States and Republican candidate in the upcoming Presidential Election.”

“THE WORK WAS ABSOLUTELY EXCELLENT. I AM VERY PROUD TO BE AN AMERICAN!” he wrote.

Secret Service agents accompanying Trump shot a man armed with an AK-47 rifle on or near the Trump International Golf Course on Sunday. The incident came about 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 murder.” Multiple law enforcement sources told ABC News that 58-year-old Ryan Wesley Routh was arrested by Florida authorities in connection with the incident.

RELATED: What we know about Ryan Wesley Routh, the suspect in the “attempted assassination” of Trump

Palm Beach County Sheriff Ric Bradshaw said at a news conference Sunday afternoon that the shooter was 300 to 500 yards from Trump when he was spotted. Secret Service agents fired four to six shots at him before he dropped his weapon and fled the scene in a vehicle. Witnesses reported the license plate number to authorities and the suspect was stopped and arrested.

It was not clear whether the suspect had pointed his gun at the former president. Agents shot the suspect after spotting his rifle through the fence, multiple sources told ABC News.

Sources said three shell casings believed to belong to the suspect's AK-47 were found at the scene, although investigators are still investigating whether the suspect fired his weapon. The rifle and two backpacks containing a GoPro camera and ceramic tiles were recovered from the scene, Bradshaw said.

According to sources, Trump was immediately taken to a secure area on the golf course grounds after the shooting.

RELATED: How the first assassination attempt on Donald Trump unfolded

Authorities are currently investigating Routh's background. Sources say the arrested man has ties to North Carolina and Hawaii. Sources told ABC News that the FBI is conducting a comprehensive investigation into Routh's social media activity, travel and any criminal history. Friends, family and acquaintances are also being sought for interviews.

Sources familiar with the investigation said authorities are investigating whether Routh had complaints related to Trump's stance on Ukraine.

Sources told ABC News that authorities will file charges in the coming days.

Both President Joe Biden and Vice President Kamala Harris condemned the apparent assassination attempt.

“As I have said many times, there is no place for political violence or violence of any kind in our country. I have directed my team to continue to ensure that the Secret Service has all the necessary resources, capabilities and protections to ensure the former president's continued safety,” Biden said in a statement.

Harris said she was “grateful” that Trump was safe and “deeply troubled by the possible assassination attempt.”

“As we gather the facts, I will be clear: I condemn political violence. We must all do our part to ensure that this incident does not lead to further violence,” Harris said.