Doug Jones was confirmed as Alabama's first Democratic senator in 25 years after state officials rejected a challenge to the shock result by his defeated Republican rival, Roy Moore.

Mr Jones, whose victory was ratified by John Merrill, Alabama's secretary of state on Thursday afternoon, will be sworn in by Vice President Mike Pence on January 3 when the US Senate returns.

The election was upheld shortly after Montgomery Circuit Judge Johnny Hardwick denied Mr Moore's request for a restraining order, which would have prevented Alabama's canvassing board certifying the result.

It leaves the Republicans with a wafer-thin Senate majority of 51 to 49.

With John McCain, the Arizona GOP senator, being treated for cancer, the Republican majority is fragile especially with other Republicans, including Susan Collins of Maine, ready to break ranks with Mr Trump on issues such as the repeal of Obamacare.