Jeremy Corbyn said he was "not interested in playing parlour games" over whether Nigel Farage will field Brexit Party candidates in Labour marginals.
But Mr Corbyn said he wasn't interested in "who may do this, who might do that" during the General Election.
Speaking in Blackpool, the Labour leader said he was focused on the party's manifesto "to end austerity" and create "an egalitarian society."
And Mr Corbyn spoke of an alliance between Donald Trump, Nigel Farage and Boris Johnson, after Mr Farage's decision not to contest Tory seats.
While Shadow Education Secretary Angela Rayner said the Conservative and Brexit Party were now "the same party."
She added: "It's absolutely clear now for many voters in this country that you want a different tact for this country, you want future for this country, you vote Labour on December 12.
"If you want a hard right deal between Donald Trump, Nigel Farage and Boris Johnson, you vote Brexit or you vote the Tories, because it is the same party."
But to the applause of the audience, she said "she does not fear the Brexit Party."
The Brexit Party leader has insisted the “difficult decision” to stand candidates down, amid fears it could lead to a hung parliament and a second referendum, had put the country “on the best possible course for future success”.
And it was reported he refused to rule out a further withdrawal, even though he vowed in a column for The Daily Telegraph that the party would focus on fighting every Labour-held seat.
Asked if he might “back-pedal” and not challenge Tory candidates in marginal seats, Mr Farage was quoted by The Telegraph as saying: “I have just taken 48 hours to make this decision – allow this one to settle first.”
According to the Financial Times, Mr Farage said: “I’ve not considered this at this moment in time. But there isn’t much time.”
And The Sun quoted senior Tories, including Iain Duncan Smith, urging the former Ukip leader to back off.
The ex-Conservative leader told the paper: “It’s a good start but if they want to deliver Brexit they’ve still got to focus on the fact that if they divide the vote they’ll let Labour in.
“He’s going to have to go further. This is a game of two halves — we’ve had the first half and now we’re going to have the second half.
“The second half is where he gets to decide which seats he stands down from, and he’s going to have to stand down from some of them.”
Rishi Sunak, Chief Secretary to the Treasury, told ITV News, he "hopes Nigel Farage realises that a vote for anyone else is not a vote that will help deliver Brexit."
"The only party that can deliver Brexit, if that's something you can about...the only party that can deliver that is a majority Conservative government," Mr Rishi said.
Mr Farage’s announcement on Tuesday was welcomed by the Prime Minister, who said it was recognition that only the Conservatives could “get Brexit done”.
But opposition parties said the move showed the Tories and the Brexit Party were now “one and the same”.
According to BBC’s Newsnight, the decision came after a message from the Brexit Party to the Tories that Mr Farage needed a public declaration on two issues – that the transition period would not be extended and that he would negotiate a Canada-style free trade deal with the EU.
Writing in The Telegraph, Mr Farage said he saw “a chink of light” when he viewed the video posted on Twitter by Boris Johnson at the weekend.
Mr Johnson said he would not extend the planned transition period beyond the end of 2020 and that he would seek a “super-Canada-plus” style free trade agreement with the EU.
Writing in The Telegraph, Mr Farage said: “Now, The Brexit Party will focus its energies on fighting every seat held by Labour, which has betrayed more than five million of its voters, and all the Remainer parties.
“If we can win some of these seats, our presence in parliament will keep Boris Johnson honest and help to deliver Brexit.
“I have no great love for the Tories, but I can see that by giving Johnson half a chance we will prevent a second referendum. To me, that is the single most important thing for Britain. No matter how it is achieved.”
But Liberal Democrat Brexit spokesman Tom Brake, responding to the reports that the pro-Brexit European Research Group held talks with the Brexit Party over Mr Farage’s decision to stand down candidates, said: “These talks show that Nigel Farage is pulling the strings behind the scenes. He is the puppet master in Boris Johnson’s Brexit horror show.
“Every vote for the Conservatives is a vote for an extreme Brexit agenda backed by Nigel Farage.”
While campaigning in Hartlepool on Tuesday, Mr Farage claimed he was offered a peerage last Friday.
“Ridiculous – the thought they can buy me, a high-paid job; but I’m not interested, I don’t want to know,” he told the Daily Mirror.
Labour leader Jeremy Corbyn said Mr Farage’s move could pave the way to a US trade deal, giving American pharmaceutical companies access to the NHS.
“One week ago Donald Trump told Nigel Farage to make a pact with Boris Johnson. Today, Trump got his wish. This Trump alliance is Thatcherism on steroids,” he said.
Asked if Mr Farage may pull out more candidates, Benyamin Habib of the Brexit Party told Newsnight: “This wasn’t choreographed. I think this was a decision that was come to after great consideration by Nigel.”