Donald Trump declared war on the Republican establishment today, lashing out at House Speaker Paul Ryan, Senator John McCain, and other GOP elected officials as the extraordinary turbulence within the Republican Party intensified four weeks from Election Day.

One day after Ryan said he would no longer campaign on Trump's behalf, the GOP nominee said as part of a barrage of tweets that Ryan was "weak and ineffective" and had provided "zero support" for his candidacy. Trump also declared that "the shackles have been taken off" him, freeing him to "fight for America the way I want to".

Trump called McCain "foul mouthed" and accused him with no evidence of once begging for his support. McCain is no longer backing Trump.

In perhaps the most piercing insult of them all, Trump said his party was harder to deal with than even Democratic rival Hillary Clinton, who is loathed by conservatives.


"Disloyal R's are far more difficult than Crooked Hillary," he wrote on Twitter, his preferred platform for igniting rhetorical fights against his foes. "They come at you from all sides. They don't know how to win - I will teach them!"

The bevy of attacks directed at his fellow Republicans for his more than 12 million Twitter followers highlighted the fierce backlash that Ryan and his allies are bracing for during the final stage of a campaign that has already wreaked havoc on the party.

In backing away from Trump, Ryan and others are hoping to insulate themselves and their majorities on Capitol Hill from the baggage weighing down Trump's flagging campaign. For many, the breaking point was a 2005 video reported by the Washington Post on Saturday in which Trump is heard making vulgar comments about physically forcing himself on women.

But in doing so, they are already absorbing counterattacks from Trump and his loyal army of supporters. Many Trump boosters say they have been emboldened by the fight and are determined to exact punishment on the party establishment's down-ballot Republican candidates.

"I do think he's going through one of those phases where he's going to get his rebuttals out there for the circumstances that have unfolded starting yesterday. And I understand why he would feel frustrated," Congressman Steve King said on CNN speaking of Trump, whom he supports.

Trump dispensed with his Twitter attacks during a light day on the campaign trail.

Ryan said yesterday that he would no longer defend or campaign with Trump. McCain pulled his support completely on Sunday in the wake of the 2005 tape. Dozens of other Republican elected officials have gone even further, calling on Trump to leave the race.

"Paul Ryan is focusing the next month on defeating Democrats, and all Republicans running for office should probably do the same," Ryan spokesman Brendan Buck said, responding to Trump's attacks.

While Ryan is wagering that turning his attention away from Trump will save many Republican House colleagues, some Trump loyalists are trying to ensure the plan backfires.

Trump spokeswoman Katrina Pierson tweeted yesterday that she could not keep her mobile phone charged "due to the mass volume of texts from people" who plan to vote for Trump but not other Republicans on the ballot.

Diana Orrock, a Republican National Committeewoman from Nevada, said she is not voting for Republicans who don't support Trump - including Joe Heck, who is running for a seat that is critical in the battle for the Senate majority.

"We just had part of our Nevada delegation who's running withdraw their endorsement for Trump and I am going on the record and withdrawing my support for them," Orrock said on CNBC. "Let the chips fall where they may."

Some Republicans have agonised over how to deal with Trump during the final weeks of the race. Senator Marco Rubio of Florida, who ran against Trump in the GOP primary and is running for re-election in a key battleground state, issued a statement saying he continues to support the nominee, whom he once called a "con man".

"I disagree with him on many things, but I disagree with his opponent on virtually everything," Rubio said. "I wish we had better choices for president. But I do not want Hillary Clinton to be our next president. And therefore my position has not changed."