TALLAHASSEE, Fla. — Looming recounts in top Florida election contests, including the bitterly fought races for Senate and governor, erupted late Thursday into a fiery feud as Gov. Rick Scott, the Republican nominee for Senate who claimed victory on Tuesday, sued local elections officials in two of the state’s largest counties and accused them of “rampant fraud.”

Standing on the steps of the Governor’s Mansion, Mr. Scott announced on Thursday night that his Senate campaign had sued the Democratic elections supervisors of Broward and Palm Beach Counties. He then asked the Florida Department of Law Enforcement, which he helps oversee as governor, to investigate them.

“The people of Florida deserve fairness and transparency, and the supervisors are failing to give it to us,” Mr. Scott said. “Every Floridian should be concerned there may be rampant fraud happening in Palm Beach and Broward Counties.”

“We’ve all seen the incompetence and irregularities in vote tabulations in Broward and Palm Beach for years,” he added, “but here we go again. I will not sit idly by while unethical liberals try to steal this election from the great people of Florida.”