RICHMOND, Virginia (CNN) -- The FBI is conducting a preliminary investigation into allegations that some voters in at least 10 counties in Virginia received deceptive calls prior to the midterm elections, law enforcement sources told CNN.

Virginia election officials expressed concern about the calls Monday, but were hesitant to launch an immediate investigation for fear of politicizing the vote.

James Alcorn, policy advisor for the Virginia State Board of Elections, said Monday that the board had notified the U.S. Department of Justice and the state's attorney general's office, but that neither state nor federal officials were likely to "get involved" until after the election. The immediate response to the allegations, he said, was voter education.

Alcorn said the state board had received a "handful" of calls and complaints about alleged deceptive phone calls made to potential voters. Jean Jensen, secretary of the board, said it had received two notarized complaints, one from a voter in Arlington and the second from a man in Northampton County.