GRAND RAPIDS, Mich. — An FBI agent said Tuesday that some of those charged in a plot to kidnap Michigan Gov. Gretchen Whitmer also discussed "taking" Virginia Gov. Ralph Northam, who reacted to the news by accusing President Trump of fueling extremism with reckless rhetoric.

The disturbing allegations about politically motivated violence surfaced during a day-long court hearing over what law enforcement officials say was a plan to abduct Michigan's highest elected official and either leave her on a boat in the middle of a lake or put her "on trial" before a self-styled militia.

Northam, like Whitmer a Democrat, said that as a former Army doctor he had faced threats from foreign enemies but never before from his own commander in chief.

"These threats and this rhetoric is not coming from another country," the governor said at an afternoon news briefing in Richmond. "It's coming from Washington. And that I regret, and it needs to stop."

The White House responded by criticizing the two governors.

"President Trump has continually condemned white supremacists and all forms of hate. Governor Whitmer, and now Governor Northam, are sowing division by making these outlandish allegations," press secretary Kayleigh McEnany said in a statement. "America stands united against hate and in support of our federal law enforcement who stopped this plot."

During the hearing here in Grand Rapids to discuss the charges filed last week against members of a self-proclaimed militia accused of plotting to kidnap Michigan’s governor, FBI Special Agent Richard Trask revealed that months ago, some of the suspects met in Dublin, Ohio, where Northam was also discussed as a potential target.

“At this meeting, they discussed possible targets, taking a sitting governor, specifically issues with the governors of Michigan and Virginia, based upon the lockdown orders,” Trask told the court, referring to state-mandated restrictions implemented to combat the spread of the novel coronavirus.

No one has been charged with plotting to kidnap Northam, but, like Whitmer, Virginia’s governor was the target of intense criticism over the summer from conservatives angry at state-mandated restrictions amid the pandemic. Trump has sharply criticized both governors, tweeting all-caps demands in the spring that their states be “liberated.”

Northam spokeswoman Alena Yarmosky said that the FBI “alerted key members of the Governor’s security team throughout the course of their investigation” but that to keep tight control of information about such a sensitive matter, neither the governor nor other members of his staff were told.

“At no time was the Governor or his family in imminent danger,” Yarmosky said, adding that extra security measures “have been in place for Governor Northam and his family for quite some time, and they will remain.”

Tuesday’s hearing was held in part to determine whether some of those charged in the alleged Whitmer plot can be released on bond.

Trask, the FBI agent, described in detail how federal agents became concerned about the accused, particularly after a June meeting in Dublin, where more than a dozen self-styled militia members from four or five states gathered to discuss possible plans.

It was at that meeting, Trask said, that the notion of grabbing governors was raised, specifically mentioning the governors of Michigan and Virginia. One of the suspects, Adam Fox, then returned to Michigan and began recruiting possible accomplices for such a kidnapping, Trask said.

Fox and others conducted surveillance on Whitmer’s lakeside vacation home, Trask said, and at one point, Fox told the others that he wanted to abduct the governor, take her away from the home by boat, and then “leave her out in the boat” so others would have to come rescue her, according to testimony at the hearing.

Another option discussed was to take Whitmer to a secret location where they would put her “on trial,” Trask said, possibly in Wisconsin.

The hearing began with five of the defendants being led into the courtroom in handcuffs, all but Fox wearing masks because of the coronavirus. A sixth defendant, Barry G. Croft Jr., attended a hearing Tuesday in federal court in Delaware, where the 44-year-old was arrested last week and awaits transfer to Michigan. Separately, state authorities in Michigan have charged seven others with providing support to terrorist acts.

U.S. Magistrate Judge Sally Berens ruled Tuesday that one of the suspects, Kaleb Franks, could not be released from jail because he posed a danger to the community. She also denied bail for another suspect, 23-year-old Daniel Harris, a Marine Corps veteran who, she said, could still try to flee or hurt someone.

“While this plot appears to be disrupted, it’s not clear that this movement has ended,” Berens said.

Earlier in the day, defense lawyers for the suspects had suggested their clients might be prone to “big talk” but were not leaders of the plot and might not have known about key elements of any kidnapping plan.

Gary Springstead, a lawyer representing 24-year-old Ty Garbin, called it “a serious case” but added that “there’s been lots of cases where serious allegations don’t bear out in the proofs in court,” citing in particular a 2010 case against a self-declared militia group in which a judge later tossed charges of sedition filed by the Justice Department.

“I think it’s important to everybody, including the public, to let this play out in court and trust the system,” said Springstead.

Trask spent hours on the witness stand describing conversations and group text messages among the suspects, who he said repeatedly discussed plans to attack law enforcement officials. At one point, a member of the group mentioned the possibility of attacking Michigan State Police buildings, he said.

At another point in the investigation, one of the defendants, Brandon Caserta, became irate because he had been pulled over and ticketed for driving without insurance.

“An injustice just happened to me,” he messaged the other suspects, according to evidence introduced at the hearing, and he wrote that he could find out where the two police officers lived and “tap them,” which Trask said is slang for killing them.

The judge denied bail for Caserta as well. A bail hearing for two other defendants is scheduled for Friday.

Even as the FBI closed in on the group, the defendants became increasingly concerned that they might be under investigation by federal agents. Trask said the accused collaborators once scanned one another’s bodies for radio signals, to see whether anyone was wearing a recording device. Although the scans turned up nothing, the group’s alleged plot was infiltrated by two informants and two undercover agents, Trask said, and the FBI secretly monitored more than 100 hours of the suspects’ conversations.

Defense lawyers tried to suggest that the informants or undercover agents encouraged the suspects to commit crimes, but Trask denied that, saying their role was to get those under investigation to talk about their intentions.

Barrett reported from Washington. Vozzella reported from Richmond. Gregory S. Schneider in Richmond and Josh Dawsey in Washington contributed to this report.