President Donald Trump on Friday said he told his administration to file its lawsuit to block certification of the U.S. Senate race in Alaska if Republican Sen. Dan Sullivan loses, kicking off what many fear could become a lengthy battle between the government and states over certifying an election where the president's party is struggling.

"I'm the one that said do it," Trump told reporters as he landed for a campaign rally in Florida.

The lawsuit, filed late Thursday, centers on one of the president's longstanding complaints in the Senate race - the presence of a second candidate named Dan Sullivan, who Republicans fear could siphon away votes from the incumbent in what's likely to be a photo-finish contest with Democrat Mary Peltola, the state's former congresswoman.