The International Olympic Committee (IOC) is to decide on which city will host the games in a final vote in Buenos Aires on September 7, 2013.

The Qatari capital Doha and Baku in Azerbaijan, were excluded in what committee vice president Thomas Bach described as "the most difficult decision we have ever had to take with regard to a shortlist."

A major factor against Qatar, due to host the 2022 football World Cup, was that it planned to stage the games in October, rather than July and August, to avoid excessive summer heat.

Qatari officials vowed to bid again. "I think it's a missed opportunity for the IOC," said Doha bid leader Noora Al-Mannai. "This opportunity for 2020 has gone. There is nothing we can do. However, we don't give up. I promise you we will be back."

Baku was ruled out in the IOC's report because of a lack of infrastructure and experience in organizing large events.

"I can assure you that we will listen and learn from the feedback that the IOC has offered us and then we will come back again next time even stronger," said Azeri Sports Minister Azad Rahimov.

Tokyo received the highest praise in the IOC report, as "a very strong application." Madrid was judged to have submitted a "strong application," while Istanbul's project was said to offer "good potential."

rc/jm (AP, AFP, dpa, Reuters)