Conservative MP Louise Mensch said she was proud to speak at a Jewish student conference despite criticism from anti-Israel bloggers.
Mrs Mensch was guest speaker at Sunday's Stand With Us – Israel in Focus conference. Before her speech, she was attacked in a post on the website of the Liberal Conspiracy magazine.
Anti-Israel activist Ben White wrote that her appearance at the event was "troubling" and accused Stand With Us of adopting "extreme positions and working with disturbing allies".
He concluded: "Should an MP be giving them support?"
But Mrs Mensch hit back on social networking site Twitter, criticising the magazine's editor, Sunny Hundal, for supporting Mr White. She highlighted Mr White's defence of a German politician who compared Israel to Nazi Germany and a 2002 article in which he wrote "I do not consider myself an antisemite, yet I can also understand why some are".
She told Mr Hundal: "You really should be ashamed of yourself, and your blog, for hosting a man with such repellent views."
At the conference, Mrs Mensch, MP for Corby and East Northamptonshire, cried as she recalled the Itamar terror attack earlier this year. Her criticism of the BBC's reporting of the murders of the Fogel family was widely praised by the Jewish community.
She said the conference had been "very moving" and she was glad to see Christians and Muslims attending alongside Jewish students.
Israeli ambassador to Britain, Daniel Taub, opened the event, praising Stand With Us for its work on British campuses.
The conference included lectures and workshops on countering boycotts of Israel, and a panel debate between JSoc members and Hasan Afzal of the British Muslims for Israel group.