S Senate runoff in Georgia on Wednesday, according Toa Edison research projections.

Warnock unseats incumbent Republican Senator Kelly Leffler.

But the high stakes Georgia races, which will determine control of the U.

S Senate, remain too close to call for the state's second Senate seat.

Incumbent Republican Senator David Perdue and Democratic challenger Jon Ossoff remained neck and neck as of early Wednesday morning.

The fate of President elect Joe Biden's legislative agenda largely depends on the outcome of the two races, as the Democrats must win both to flip the Senate in their favor.

The run offs a cork of state law, became necessary when none of the candidates earned half of the vote in the general election last November.

They have smashed spending and early voting records for a runoff, with an estimated 4.5 million votes having been cast.

Most of the remaining uncounted ballots early Wednesday were in counties which voted for Biden when he narrowly won the state in the presidential election.

His surprise win over President Trump in Georgia gave Democrats hope for this week's runoff in a state which has been dominated by Republicans for decades.

Warnock selection is historic, making him Georgia's first black US senator and if elected, Ossoff will become the Senate's youngest member.