More than 1.1 million Georgians have voted in twin US Senate runoff elections that will determine which party controls that chamber of Congress, and with it the fate of much of Democratic President-elect Joe Biden's agenda, state data showed on Friday.

The surge in turnout after four days of early in-person voting and about four weeks of mail-in voting showed that voter participation in the two races is on pace to rival the records set in the November contest in which Biden defeated Republican President Donald Trump.

State data published on Friday showed the number of accepted ballots was just below the level seen at the same point in early voting for the Nov. 3 presidential contest.

Ballots accepted through Thursday were only just below the 1.2 million that were cast at the same point in the November election, when turnout eventually totaled about 5 million votes.

Voting in the Senate runoffs, which are taking place because no candidate won 50% support, ends on Jan. 5.

Biden's razor-thin victory in Georgia last month amid record-high turnout underscored the Southern state's transformation from Republican stronghold to one of the country's most competitive political battlegrounds.