Toure is required by the Ivory Coast for the tournament, which starts in Gabon and Equatorial Guinea on January 21,
The midfielder is quoted in several newspapers as saying: "Our country needs people like me and Didier Drogba at the moment. There is a war again and it's important we do what we can for our people. It is dangerous and people are afraid."
He added: "The team, the club and the manager needs me and I do feel a little bit guilty and confused about leaving.
"But I have to go because my country is going through some difficult things with the war. City will cope."
However, the Manchester City midfielder may be allowed to delay his departure so he can figure in two key cup matches. City play city rivals United in the FA Cup third round on January 8, with Liverpool visiting in the first leg of the Carling Cup semi-final three days later.
The Ivory Coast would be within their rights to summon Toure - and brother Kolo - with FIFA rules stating that participating nations can call on players to report for duty up to 14 days before the start of a major tournament.
However, Ivory Coast counterpart Francois Zahoui played alongside City boss Roberto Mancini in Italy with Ascoli - and the latter hopes to have the Toure brothers in his squad for both cup matches.
Yaya Toure is adamant, however, that City's squad is strong enough to cope with the absence of the pair, should they be required to miss both ties.
He added: "We have fantastic players who can take my place. I will not be away for a long time and I want to come back and help us win the league."