At least five US secret service agents have been placed on leave following the assassination attempt on Donald Trump in Pennsylvania, US media reports.

According to the BBC’s US news partner CBS, they include the head of the Pittsburgh field office that coordinated security measures with local police, three other agents from the same office and a member of Trump’s personal staff.

Trump, the Republican presidential candidate, was shot in the right ear by a bullet fired from a rooftop during a rally in Butler on July 13. The bullet was fired by 20-year-old Thomas Crooks.

His volley killed one member of the crowd and wounded two others before he was shot and killed by a Secret Service sniper.

Anthony Guglielmi, a Secret Service spokesman, said the investigation into this “operational failure” was ongoing. He added that agents are held to “the highest professional standards” and violations could result in disciplinary action.

Kimberly Cheatle resigned from her post as head of the service shortly after facing a controversial hearing before members of Congress and providing no concrete answers about the attack and the response of her agents.

Her successor as acting director was Ronald Rowe.

The House of Representatives has set up a task force to investigate the operational errors that allowed the crooks to fire on the crowd.

Trump held an outdoor rally in North Carolina on Wednesday, his first since the assassination. His lectern was surrounded by bulletproof glass.

BBC News has contacted the Secret Service for comment.