Declaring "the climate of this country has moved in my direction," white supremacist David Duke registered on Friday for Louisiana's US Senate race, saying he was partially spurred by the recent shooting deaths of three law enforcement officers by a black man.

"I believe my time has come," the former Ku Klux Klan leader said after submitting his paperwork for the ballot. He added: "The people of this country, the patriotic, decent, God-fearing people of this country are now right with me."

Mr Duke's candidacy comes one day after Donald Trump accepted the GOP nomination for president, and Mr Duke said he's espoused principles for years that are similar to the themes Republicans are now supporting in Trump's campaign, on issues such as immigration and trade.

He said Americans were "embracing the core issues I have fought for my entire life."

Mr Duke, 66, is registered with the GOP, but Republicans at the state and federal level quickly denounced his Senate bid.