Democrat Ruben Gallego has beaten Republican Kari Lake in their closely watched US Senate race in Arizona, the BBC's US partner CBS News projects.

Gallego, a 44-year-old Iraq War veteran who has served in the US House of Representatives, has a lead of about two points over Lake, 55, a former news anchor and an outspoken ally of Donald Trump.

The contest came two years after Lake - who denies that Trump lost the 2020 presidential election - lost the Arizona governor race; a result she also challenged.

Gallego's win represents some solace for Democrats, in a swing state that went against them in the presidential election, and in the overall battle for control of the Senate.

Gallego will become the first Latino to represent Arizona in the US Senate, replacing independent lawmaker and former Democrat Kyrsten Sinema.

The battleground state of Arizona had not elected a Democratic US senator for 30 years before Sinema won her seat, followed by fellow Democrat Mark Kelly, who won John McCain's seat in 2020 after he died.

Having entered politics with progressive positions, Gallego was observed by pundits to be running on a more moderate platform in 2024.

He emphasised his military background, and promised to lower rising costs and to fix a "broken" immigration system in the border state.

Lake, meanwhile, frequently attacked Gallego's personal life, including the criminal background of his estranged father. She consistently trailed Gallego in the polls leading up to the race.

Next year, the Republican Party will take control of the Senate, or upper chamber of US Congress, with a narrow majority.

Meanwhile, they are a handful of seats short of winning majority control of the House, or lower chamber - though several races remain too close to call.