Three MEPs are quitting the UK's Brexit Party and urging people to back the Conservatives at the upcoming British general election.
Annunziata Rees-Mogg - the sister of UK cabinet minister Jacob Rees-Mogg - as well as Lance Forman and Lucy Harris are due to announce their decision later.
They will urge voters to support the Conservatives on polling day in Britain.
Ms Rees-Mogg said: "We need a strong leave-supporting government to deliver the Brexit 17.4 million voted for.
"The Conservatives are the only option for Brexit supporters and democrats alike."
Nigel Farage, the leader of the Brexit Party, said he was "disappointed" at the news.
He claimed that after he stood down candidates in all Conservative-held seats and called on Prime Minister Boris Johnson to reciprocate in other areas, the MEPs' decision would only split the leave vote in Labour heartlands.
"We are disappointed that four of our MEPs don't seem to understand that we both saved the Conservative party from large scale losses to the Liberal Democrats in the South and South West of England," Mr Farage said.
"We are also hammering the Labour leave vote in its traditional heartlands making it much easier for the Conservatives to win many of those seats.
"The only vote on the leave side that is currently being split is in areas such as Barnsley, the South Wales valleys, Doncaster and Hartlepool where there is a risk that the Tories will split our vote."
A party spokesman added: "We also note that one of the MEPs is the sister of a cabinet minister, another has a partner who works in the office of the same cabinet minister, and yet another is a personal friend of both Boris Johnson and Michael Gove."
Earlier on Thursday it was announced four Brexit MEPs had quit. It was later clarified that MEP John Longworth was kicked out of the party for "repeatedly undermining" their election strategy.
He had previously called on them to stand down more candidates and only pursue "20 or 30" constituencies.