The Momentum group of Labour activists will not campaign for the deselection of moderate MPs, its chairman has claimed.
Jon Lansman denied reports that the group's supporters had drawn up a deselection hit-list of 50 centrists, including Hilary Benn and Angela Eagle.
"We have made it clear that we are not going to campaign to deselect anyone, at all, anywhere," he said.
But the veteran left-winger said it was up to local constituency parties if they wanted to activate the little-used "trigger ballot" process to prevent their MP from standing as a candidate at the next general election.
No Labour MP who "listens to their members" should have anything to fear from the process, he said.
Fears of a purge of centrist MPs have grown since three Momentum-backed candidates, including Lansman, were elected on to Labour's ruling National Executive Committee last week.
But Lansman told The Independent: "Momentum nationally is not going to campaign to deselect any MP and we will stick by that.
"We are not going to campaign to deselect any individual MP."
Reports of a "deselection hit-list" of MPs critical to Corbyn had "no factual basis whatsoever," he said.
Lansman - a former aide to Tony Benn - said it "wouldn't be surprising" if local constituency parties made use of the trigger ballot process to ditch MPs who did not try to perform well.
But he insisted: "No Labour MP that works hard and campaigns and listens to their members has anything to fear from the selection process."
Bermondsey and Old Southwark MP Neil Coyle, who has been the target of criticism from left-wingers, told the paper Lansman's comments were "welcome".
But he added: "Lansman's real challenge is in ensuring Momentum members at local level adhere to his commitment."
And Nottingham East MP Chris Leslie - a former shadow chancellor who was reportedly included on the supposed deselection hit-list - said: "The Momentum leadership are constantly obsessing about process.
"It is an attempt to instil fear into every single member of the Parliamentary Labour Party, whether they are on the frontbench or the backbench, that the threat to their job is always there if they dare disagree."