A senior TikTok employee has warned that its moderators have openly expressed "support for terrorism or endorsed extremist movements" that work against Israel.

Their views are why the platform contains so much “hostile propaganda against Israel and Jews”, the employee in the firm’s Israel office explained in a memo to senior management

The employee also raised concerns that the Chinese-owned company refused to allow adverts about Israeli hostages, unlike Facebook and Instagram, but did allow those from pro-Palestinian groups.

Screenshots obtained by Fox News Digital from TikTok’s internal employee chat platform, Lark, show Trust and Safety officers celebrating Hamas and other Iranian-backed terror groups.

In one, a moderator expressed thanks to TikTok for not removing the controversial account of a Palestinian photographer based in Gaza who allegedly shared fake content in support of Hamas.

A TikTok employee in Nashville, Tennessee, broke state legislation to promote guidelines from the Boycott, Divestment, and Sanctions movement against certain US products and companies that are connected to Israel.

The memo states that TikTok has created an extremely hostile environment for Jewish and Israeli employees. It says many employees - particularly moderators - have openly expressed "support for terrorism or endorsed extremist movements" that work against Israel.

"This, very likely, influences the amount of hostile propaganda against Israel and Jews and harmful misinformation on our platform, both in the USA and Europe," the Israeli employee behind it said.

The memo reads: "Labelling kidnapped babies, women, children, and elderly citizens who were taken from their beds by Hamas-ISIS as a ‘political issue’ is, at the very least, one-sided.

"This way, American users are BOMBARDED with paid ads that present the misery of children in Gaza (not mentioning, of course, the massive humanitarian aid entering Gaza and stolen by Hamas as indicated by the UN), some with a high budget (according to our own company's top ads creative centre) while ads that show the humanitarian tragedy of Israeli hostages cannot be presented to these audiences."

Yossi Lubaton, an advertising professional behind the campaign to highlight Israeli hostages, said: "We were told that according to their policy, we were unable to place paid campaigns because they were considered too political or too graphic.

"They told us it was a strict policy that was applied to the Israeli side, as well as to the other side, and so we started to put the paid campaign on Facebook and Google instead."

TikTok said it does not allow political advertising, "including the use of campaign slogans," and that it also prohibited ads that contained "depictions of war, weapons, hostages, and violence."

However, it allows humanitarian adverts campaigns from non-profit organisations.

A spokesperson for TikTok said: "These allegations are false and do not reflect TikTok policies in any way.

"We are clear in our advertising policies what content is allowed to be advertised and apply those policies equally to all ads on TikTok.

"We invest heavily in training our moderators to apply these policies consistently."