During the campaign, Trump called to ban Muslims from entering the U.S.

The revelation comes days after U.S. Department of Homeland Security officials told Wisconsin election officials that Russia-linked hackers unsuccessfully targeted the state’s voter registration system in 2016.

With Wisconsin being one of the most politically divided states, Dave Schroeder, a U.S. Navy intelligence officer and cybersecurity expert at UW-Madison, said it’s no surprise Russian actors are targeting it. Doing so provides “the highest return on investment,” he said.

Schroeder said the interference efforts hint at more to come in future elections.

“Because states like Wisconsin and Michigan will be critical to elections, and because of the apparent success of these operations to date, we can expect to see more of it,” Schroeder said.

That mirrored what Burr and the lead Democrat on the Senate Intelligence Committee, Sen. Mark Warner of Virginia, said in a Wednesday news conference.

“The Russian intelligence service is determined, clever and I recommend every campaign and every elected official take this seriously,” Burr said.