In a startling revelation, US authorities have obtained intelligence from a human source regarding an Iranian plot to assassinate former President Donald Trump. Multiple sources, who were briefed on the matter, informed CNN that this development led to the Secret Service beefing up security measures around Trump in recent weeks. However, it is important to note that there is no indication that the would-be assassin, Thomas Matthew Crooks, who attempted to attack the former president on Saturday, was connected to the plot.

The existence of this threat, coupled with the heightened security for Trump, has raised concerns about the security lapses that resulted in the shooting incident during a rally in Butler, Pennsylvania. How a 20-year-old suspect managed to access a nearby rooftop and fire shots, injuring the former president, has left many questioning the effectiveness of security protocols.

A US national security official disclosed that both the Secret Service and the Trump campaign were made aware of the threat prior to the rally. In response, the Secret Service increased resources and assets to ensure the protection of the former president. The Trump campaign, however, declined to comment on whether they were informed of the Iran threat, directing all inquiries to the Secret Service.

Inside sources reveal that Secret Service officials have repeatedly cautioned the Trump campaign against holding outdoor rallies, citing increased risks compared to events where access can be better controlled. While these warnings were more general in nature, they underscore the ongoing need for vigilance in the face of potential threats.

The investigation into Saturday's shooting incident is being conducted by the FBI, who declined to comment on the matter. The National Security Council (NSC) spokesperson, Adrienne Watson, clarified that as of now, there is no known link between the shooter and any accomplice or co-conspirator, foreign or domestic.

Denying the existence of an Iranian plot, the Permanent Mission of the Islamic Republic of Iran to the United Nations labeled the accusations as "unsubstantiated and malicious." They emphasized their commitment to seeking legal justice for the killing of General Qasem Soleimani and expressed their view of Trump as a criminal who should face prosecution.

This recent plot follows past instances where Iranian officials have vowed revenge for Soleimani's killing. In August 2022, criminal charges were brought against a member of the Islamic Revolutionary Guard Corps for allegedly attempting to orchestrate the assassination of John Bolton, former national security adviser to Trump. Former Secretary of State Mike Pompeo was also identified as a target of the Iranian plot.

Former senior Trump administration officials, including Robert O'Brien, Trump's former national security adviser, have faced threats from Iran. While O'Brien had a US government security detail, it was terminated last summer, prompting him to arrange his own private security. Despite this, John Bolton continues to have the protection of a Secret Service detail.

Law enforcement officials have expressed ongoing concerns regarding the persistent threat posed by Iran, particularly against former Trump officials and the former president himself. The recent intelligence has indicated an increase in this threat, coinciding with a surge of online messaging from Iranian sources referencing Trump, thereby heightening security concerns among US officials.

As the investigation unfolds, authorities remain determined to ensure the safety and security of all individuals involved, as well as to prevent any potential threats from materializing.

CNN's Josh Campbell contributed to this report, which has been updated with additional developments.