The practice was commissioned to design the 300m-high skyscraper for the massive Russian energy firm after winning a competition that included the likes of Rem Koolhaas, Jean Nouvel, Daniel Libeskind, Herzog & de Meuron and Massimiliano Fuksas.
The move echoes two incidents in Liverpool and London earlier this year, where UNESCO warned both cities that they would lose their heritage status for developments near the Princes Dock and the Tower of London respectively.
According to the deputy director general of Unesco Marcio Barbosa, the Russian city has until February 2008 to submit a report on the building's potential impact.
Speaking to the Guardian, Barbosa said: 'It is like in football, a yellow card. If the situation does not change we will seriously be considering putting the site on a list of sites that are in danger.'
The twisting steel and glass tower is being worked on both in the UK and from RMJM's Moscow office.
Tony Kettle, UK managing director of RMJM, said: 'We are continuing to consult with interested heritage groups, including UNESCO, over the coming weeks and will be providing them with full details of the design proposals.
'It would not be appropriate to comment further until such bodies feel fully informed.'