His assertion came in response to the news on Saturday that the Florida Secretary of State ordered a machine recount of votes in the U.S. Senate race, as well as the governor's race. The results are due by 3 p.m. ET Thursday.
Trump tweeted, "Trying to STEAL two big elections. We are watching closely!"
Republican Gov. Rick Scott and Democrat Bill Nelson are locked in a tight battle for Florida's Senate seat. Scott's lead over Nelson narrowed to about 12,500 votes, or 0.15 percent, by Saturday afternoon.
In the gubernatorial contest, Republican Ron DeSantis, a former congressman, was last leading by 0.41 percentage points over Democratic Tallahassee Mayor Andrew Gillum.
Earlier in the day, a motion was approved in Broward County to begin a recount in four Florida races, including the senate and governor races.