Jeremy Corbyn is "hiding behind a closed door" over calls for him to step down, his rival Angela Eagle has said ahead of her UK Labour leadership bid.
Ms Eagle, who recently quit as shadow business secretary, insisted her bid to take over the party and oust Mr Corbyn is about uniting Labour, not splitting it.
The UK Labour leader said he was "disappointed" that she was poised to challenge him and said he will fight for the leadership.
Speaking to ITV's Peston on Sunday, Ms Eagle said: "I don't think he's been able to communicate with the electorate and he's now lost the confidence of the parliamentary (Labour) party.
"Tom Watson, our deputy leader who's got his own mandate, Rosie Winterton, the chief whip, John Cryer, who's chair of the Parliamentary Labour Party and a friend of Jeremy's, have all been trying to get him to recognise that he cannot continue in the job because he's lost confidence of the PLP.
"He's hiding behind a closed door, denying that this is a fact. That's not leadership."
Predicting an early election, she added: "There could easily be a very quick general election and I believe I'm the right person to lead the Labour Party into that general election."
But the Labour leader urged Ms Eagle, who was the most senior member of his shadow cabinet to quit in protest during the recent turmoil, to "think for a moment" about her actions.
On BBC One's Andrew Marr Show Mr Corbyn said he had "reached out in a way no other leader has" in an attempt to unite all parts of the party.
Mr Corbyn said he expected to be on the ballot paper as the incumbent leader - an assertion disputed by his opponents.
"I'm expecting to be on the ballot paper because the rules of the party indicate that the existing leader, if challenged, should be on the ballot paper anyway," he said.
Responding to Ms Eagle's decision to launch a challenge, he said: "I'm disappointed, but obviously she is free to do that if she wishes to.
"We have worked together in the past nine months in the shadow cabinet and this is an opportunity when we could be putting enormous pressure on this Tory government."