The United States received intelligence in recent weeks about an Iranian plot to assassinate former U.S. President Donald Trump, CNN reported.
The White House said there were no indications that the suspected shooter in Saturday's attempted assassination of Trump had any foreign or domestic accomplices.
Iran said the accusations against it were "unsubstantiated and malicious."
U.S. officials have for years worried that Iran would retaliate against Trump for his ordering of the January 2020 killing of Iranian military commander Qassem Soleimani.
A U.S. official said that on learning of the increased threat, the National Security Council contacted the Secret Service, which added resources and assets for Trump's protection.
The Trump campaign was also made aware of an evolving threat, the official said.
