The UN Department for Safety and Security, which works with Egyptian police to secure the summit, said Monday it had "been made aware of allegations" of violations of the code of conduct and was "investigating these reports."

But Wael Aboulmagd, representative of Egypt's presidency of the COP27 said the allegations were "ludicrous", he told reporters.

"Some people we've been talking to, from the developing world in particular, are tired of these apparently intentional distractions from climate issues," Aboulmagd said.

Claims surfaced after the German delegation hosted an event featuring Sanaa Seif, sister of jailed hunger-striker and pro-democracy activist Alaa Abdel Fattah.

Seif was heckled by pro-government attendees at two press conferences, who called her brother a "criminal", not a "political prisoner".

Seven months into a hunger strike, Abdel Fattah escalated his fast to include water on November 6 as world leaders arrived for COP27 to protest the conditions he said he and about 60,000 other political prisoners face in the country.

He has since started taking liquids again, according to a letter that prison authorities handed to his family on Monday.

'Watched' 

Egypt, which has sought to burnish its image by hosting the climate talks, has come under fire during the summit over its human rights record, with the fate of Abdel Fattah grabbing attention.

A German diplomatic source said a complaint was lodged with Egypt as the delegation "felt we were being watched."

Liane Schalatek, associate director of the Heinrich Boll Stiftung foundation in Washington, told Germany's ZDF broadcaster that said she felt "watched" and was "clearly more uncomfortable than at any other COP before."

Schalatek, a climate finance expert who has attended COP conferences since 2008, says this time cameras in meeting rooms were directed at the faces of speakers.

"This is both unnecessary and unusual for such internal coordination meetings," she said. "The possibility that everything is being recorded cannot be ruled out."

Human Rights Watch had previously condemned Egypt's "sweeping surveillance" plans, which included the installation of cameras in hundreds of taxis in Sharm al-Sheikh.

The New York-based rights group also warned that Egypt's smartphone application for COP27 attendees, which it said requires "access to the phone's camera, microphone (and) location", raises "surveillance and privacy concerns."