The U.S. Senate race between Republican Senator David Perdue and Democrat Jon Ossoff in Georgia appeared to be heading for a January runoff on Thursday, potentially making a pair of delayed elections that could determine control of that chamber.

Perdue, 70, a wealthy businessman and ally of Republican President Donald Trump, saw his leading share of the vote drop to 50% as ballot counting tightened his contest against Ossoff and Shane Hazel, a former U.S. Marine who is the Libertarian Party candidate.

With 98% of the vote counted, Ossoff had 47.7% and Hazel 2.3%, according to Edison Research. Under Georgia election law, a winning candidate must receive more than 50% of the vote to avoid a Jan. 5 runoff between the two top candidates. Georgia election officials have not yet ordered a runoff in that race.