Blues boss Roberto Mancini expressed the hope that the pair would be allowed to join the Ivory Coast squad for this month's African Nations Cup slightly later than planned, which would allow them to feature in the third-round tie at the Etihad Stadium.
City were unaware of any official developments on Thursday lunchtime, however, Ivory Coast coach Francois Zahoui has since apparently said no, telling BBC Africa: "Clubs know the rules. I'm expecting them [the Toures] for the FIFA deadline."
Prior to the announcement Mancini said that he expected to learn within 24 hours whether the Toures would be excused a planned squad gathering in Paris on Saturday before they fly to Abu Dhabi for a two week training camp.
If confirmed, the news will be a major blow for City, whose manager has revealed he may struggle to fill his bench on Sunday.
Gareth Barry is suspended, Owen Hargreaves is not considered fit enough to be involved and Mario Balotelli is troubled by an ankle injury that prevented him playing against both Sunderland and Liverpool.
"We have 17 players," said Mancini. "I do not know how it is going to work. I always said we could have a problem in January. Yaya is an important player for us.
"Kolo is different. We have eight defenders and if we are lucky, we don't have any injuries. In midfield we have a big problem. On Sunday we only have James Milner and Nigel de Jong available."
City officials have distanced themselves from reports that both QPR and Wolves have lodged bid for Nedum Onuoha.
However, it does appear Carlos Tevez will be moving on amid reports he has opened negotiations with Inter Milan, and Mancini added: "I do not know the situation [on Thursday] but I do hope for him he can close a deal with a team this week because he hasn't played for three months."