Madrid and Istanbul have confirmed their intention to bid for the 2020 Olympics.
They join Rome which has also indicated its intention to bid for the event with Tokyo also likely to confirm its candidacy later this week.
Qatar has also expressed an interest in hosting the event which falls just two years before the 2022 football World Cup which the country won the right to host earlier this year.
A decision on the 2020 Olympic host city won't be made until 2013.
