The FBI has underscored the ongoing threat of copycat shootings in the wake of the El Paso and Dayton mass shootings, which left at least 31 victims dead this weekend.

"The FBI remains concerned that U.S.-based domestic violent extremists could become inspired by these and previous high-profile attacks to engage in similar acts of violence," the bureau said in a statement Sunday. "The FBI asks the American public to report to law enforcement any suspicious activity that is observed either in person or online," the statement said.

In the wake of the recent attacks, FBI Director Chris Wray has told senior FBI officials to put together a new threat assessment looking at mass shootings, ABC News reports.

The FBI is currently investigating nearly 850 people across the United States as possible domestic terrorists, an FBI official said at a congressional hearing in May.