Jeremy Corbyn appeared to be tightening his grip on the Labour Party by suggesting the reintroduction of shadow cabinet elections with a members' vote and after his allies appeared to back deselection of disloyal MPs.
Mr Corbyn has said he wants to forge unity in the party but senior MPs said his claims were undermined by his shadow cabinet plans, growing murmurings of deselection among his supporters, and his refusal to deny a plot to oust deputy leader Tom Watson.
The Labour leader was accused by leadership rival Owen Smith of leaving colleagues "hanging out to dry" after refusing to intervene in alleged attempts by activists to deselect critical MPs so they cannot fight the next general election.
Mr Smith claimed pro-Corbyn pressure group Momentum is actively attempting to take over local parties and force the deselection of rebellious colleagues.
And a Channel 4 Dispatches documentary to air on Monday secretly filmed Mark Sandell, suspended chairman of Brighton and Hove Labour but not a Momentum member, telling a meeting of the pressure group that Hove MP Peter Kyle had "every good reason to feel nervous" and discussing handing out redundancy notices to MPs.
Asked by Mr Smith at a Jewish community leadership hustings if he would be "sanguine" about the allegations if they were proven, Mr Corbyn replied: "I don't think it's the job of the leader of the party, be it you or me or anybody else, to decide who the candidate is at a local level."
Hitting back at the north London debate, Mr Smith said: "I think that is hanging out to dry decent Labour MPs."
Aping Mr Corbyn, Mr Smith added: "It's got nothing to do with me, my hands are clean, if Momentum want to do that...'."
The Labour leader said many MPs will face selection battles in their seats due to proposed boundary changes but told colleagues they had nothing to fear because he has a "big heart" and is "very friendly".
Mr Corbyn has insisted he wants to reconcile with disaffected MPs and has offered them a role in picking the shadow cabinet - but also suggested members could form part of the process of electing his top team.
Labour MPs are beginning to accept that Mr Corbyn is highly likely to remain in post once the leadership contest concludes at a special conference on Saturday, and several have expressed a willingness to return to the shadow cabinet.
But Mr Smith has dismissed the idea of involving members, who overwhelmingly support Mr Corbyn, as an attempt to shore up the leader's position, while former frontbenchers such as Chris Bryant and Liz Kendall have expressed concerns.
Tom Watson is due to present alternative plans to reintroduce shadow cabinet elections by MPs, which were scrapped by Ed Miliband in 2011, but the deputy leader was said on Saturday to be open to Mr Corbyn's idea.
By Sunday, Mr Watson's position may have changed after Mr Corbyn failed to deny claims that he and his inner circle were plotting to oust him from his elected position as deputy leader.
The Labour leader told ITV's Peston On Sunday that Mr Watson and Labour general secretary Iain McNicol were "obviously part" of the discussion the group were having about the future of the party, but insisted "we're going to carry on winning together".
Former deputy Labour leader Margaret Beckett described the situation as alarming.
"There's something strange going on where on the one hand Jeremy says, with all sincerity, that he wants to see greater unity in the party but the people around him seem to be going out of their way to say and do things that will cause greater disunity," she said.
"And Jeremy doesn't seems to be very good at disassociating himself from it."
Mr Corbyn's comments at the hustings came after his ally Clive Lewis, the shadow defence secretary, backed deselection as a "democratic choice".
Len McCluskey, leader of the country's biggest trade union Unite, said critical MPs were "asking" to be de-selected with their behaviour.
He told a BBC Panorama documentary to air on Monday: "I think anybody who behaves in a way that is totally disrespectful and outwith the culture of the Labour Party is basically asking to be held to account."
James Schneider, of Momentum, denied allegations the group was pressing for mandatory re-selections.
He told Sky News's Murnaghan programme: "Momentum has been extremely clear all the way through, we are not campaigning for any deselection. We are not campaigning for mandatory selection."
Meanwhile, anti-Corbyn former Labour leader Lord Kinnock said Labour was facing its greatest crisis since the 1930s.
He told Panorama: "Unless things change radically, and rapidly, it's very doubtful I'll see another Labour government in my lifetime."