Communication breakdowns with local law enforcement hampered the Secret Service’s performance ahead of a July assassination attempt on former US president Donald Trump, according to a new report.

A five-page document summarising the Secret Service report’s key conclusions finds fault with both local and federal law enforcement, underscoring the cascading and wide-ranging failings that preceded the July 13 shooting at a Butler, Pennsylvania, campaign rally where Mr Trump was wounded in the ear by gunfire.

Though the failed response has been well-documented through congressional testimony, news media investigations and other public statements, the report being released on Friday marks the Secret Service’s most formal attempt to catalogue the errors of the day and is being released amid fresh scrutiny following Sunday’s arrest in Florida of a man who authorities say wanted to kill Mr Trump.

“It’s important that we hold ourselves to account for the failures of July 13th and that we use the lessons learned to make sure that we do not have another mission failure like this again,” Secret Service acting director Ronald Rowe Junior said in a statement accompanying the release of the report into the agency’s own internal investigation.

The report details a series of “communications deficiencies” before the shooting by 20-year-old Thomas Matthew Crooks, who was shot by a Secret Service counter-sniper after firing eight rounds in Trump’s direction from the roof of a building less than 150 yards from where Trump was speaking.

It makes clear that the Secret Service knew even before the shooting that the rally site posed a security challenge.