Fox News has learned of a Joint Intelligence Bulletin from the FBI and the Department of Homeland Security that was published this week warning of potential repeat attacks and retaliation following the shooting of former President Trump on Saturday.

The four-page bulletin, first reported on by Politico, stated that violent extremists or others "may attempt follow-on or retaliatory acts of violence" in response to the attempt on Trump's life, according to the outlet.

Fox News has not independently reviewed the full bulletin, but an FBI source tells Fox, "We continue to face very real threats from those who seek to undermine our elections. The FBI remains vigilant in our efforts to detect and assess possible threats and, as always, we encourage the public to promptly report suspicious activities which could represent a threat to public safety."

RISK OF TERROR ATTACK ON US SOIL RISES TO ALARMINGLY HIGH LEVEL, EXPERTS WARN

Donald Trump reacts as multiple shots rang out during a campaign rally

Former President Trump reacts as shots rang out during a campaign rally in Butler, Pennsylvania, on July 13, 2024. (Reuters/Brendan McDermid)

The intelligence bulletin states that extremists have conducted or plotted attacks against "perceived political or ideological opponents" and was shared with multiple intelligence and law enforcement organizations, Politico reports. 

It did not mention any specific targets, and bulletins are not unusual and often disseminated to remind people to stay alert.

"The FBI and DHS remain concerned about the potential for follow-on or retaliatory acts of violence following this attack, particularly given that individuals in some online communities have threatened, encouraged, or referenced acts of violence in response to the attempted assassination," the bulletin reads, in part, per Politico.

TRUMP ASSASSINATION ATTEMPT COULD HAVE WIDESPREAD MENTAL HEALTH IMPACT, EXPERTS SAY: ‘VICARIOUS TRAUMA’

Trump shooter graduating in a yearbook photo

Thomas Matthew Crooks, in an undated photo, who was killed by Secret Service after the assassination attempt on former President Trump on Saturday. (Obtained by Fox News Digital)

"This attack reinforces our assessment that election-related targets are under a heightened threat of attack or other types of disruptive incidents," the bulletin said, per Politico.

Trump was shot at by a lone gunman – identified as 20-year-old Thomas Matthew Crooks – at a campaign rally in Pennsylvania on Saturday, with a bullet striking his ear.

One victim, Corey Comperatore, was fatally shot while two other victims, 57-year-old David Dutch of New Kensington, Pennsylvania, and 74-year-old James Copenhaver of Moon Township, Pennsylvania, were wounded. Both are now in stable condition.

Trump is now in Milwaukee, Wisconsin, where the Republican National Committee is nominating him for president, with Sen. JD Vance, R-Ohio, as his running mate.

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Wray testifies before Congress

FBI Director Christopher Wray has repeatedly warned of a "heightened threat environment" with regard to terrorism in the U.S. (Al Drago/Bloomberg via Getty Images)

The FBI announced Sunday it is investigating the assassination attempt as a potential act of terrorism, although a motive for the attack has still to be determined. 

The bulletin comes after FBI Director Christopher Wray has repeatedly warned of a "heightened threat environment," with regard to terrorism, highlighting dangerous individuals crossing the southern border. 

Fox News' Jake Gibson contributed to this report.