Labour leader Jeremy Corbyn has said he 'removed himself' from a closed Facebook group which allegedly included anti-Semitic posts.
Mr Corbyn visited Alfreton today - International Women's Day - and met female business owners, founders and entrepreneurs.
The visit came after the Campaign Against Anti-Semitism published screenshots of messages apparently posted on the Palestine Live Facebook group.
It allegedly included discussions of conspiracy myths about the Rothschild family and supposed Israeli involvement in the 9/11 terrorist attacks, as well as links to material produced by neo-Nazi groups.
During the visit, Mr Corbyn told reporters: "I was joined on to that group without knowing it in probably about 2013-14.
"I removed myself from the group in 2015.
"I have never trawled through the whole group - I have never read all the messages on it.
"Obviously any anti-Semitic comment is wrong.
"Any anti-Semitism in any form is wrong."
Mr Corbyn said Labour 'doesn't tolerate' anti-Semitism and he would have challenged any abusive posts if he had seen them.
"Had I seen it, of course, I would have challenged it straight away but I actually don't spend all my time reading social media," he added.
Disciplinary action may take place
Mr Corbyn's spokesman said there was no suggestion the socialist had made any anti-Semitic posts.
The spokesman said: "Jeremy and the Labour Party are implacably opposed to all forms of anti-Semitism and will take whatever necessary action to stamp it out in the Labour Party.
"I don't think anyone is suggesting that anything that Jeremy has written in any Facebook group or anywhere else constitutes anti-Semitic comments.
"As I understand it, there were thousands of members of this group.
"As anyone knows, in social media all sorts of things are posted which often others participating aren't even aware of.
"It is repugnant if there are anti-Semitic posts - and I gather there are.
"If they involve anyone to do with the Labour Party then investigation and disciplinary action will be taken."
But the Campaign Against Anti-Semitism said there was 'no conceivable justification' for Mr Corbyn's involvement in the closed group and it would be filing a disciplinary complaint to the party against him.
Heated council meeting
At a Derbyshire County Council (DCC) meeting last month, Councillor Alex Dale, cabinet member for young people at the Tory-led authority, referred to Labour politicians who had been accused of making anti-Semitic remarks.
He said: "Under Jeremy Corbyn, Labour is failing to deal with anti-Semitism.
"What sort of example is Mr Corbyn setting when he's so unwilling to stamp out anti-Semitism in his own party?"
Coun Anne Western, leader of the Labour group on DCC, responded: "This is disgraceful.
"You're trying to score cheap political points with an ill-informed attack on Labour."
An internal inquiry in 2016 found that Labour was not overrun by anti-Semitism or other forms of racism but that there was an occasionally 'toxic atmosphere' within the party.