The Republican Party won a 51-seat majority in the Senate as preliminary results of the US presidential and congressional elections came in after polls closed in a number of states amid a heated contest between Republican candidate Donald Trump and Democrat Kamala Harris.

The current make-up of the Senate in the US Congress gives the Democrats 51 seats and the Republicans 49.

Under current US law, in the event of a tie in the Senate, the Vice President of the United States, who has the powers of the President of the Senate in Congress, has the final say.

The Republicans are also leading in the elections for the US House of Representatives, with predictions that they will win 159 out of 435 seats, compared to 103 for the Democrats.