UEFA decided in January that the tournament would break from tradition and be spread over 13 nations with president Michel Platini saying he wanted the final and semi-finals to be played in Turkey.
International Olympic Committee rules would prevent Turkey hosting any other major sporting event in 2020 should it win hosting rights, and the chairman of Istanbul's bid on Tuesday said the IOC's evaluation committee would be assured next month that government support is behind the Olympics.
"Istanbul is very clear," Hasan Arat told reporters in a London hotel. "It's for the 2020 Olympic bid.
"The government made the decision. There is no official interest and these comments come from UEFA.
"Istanbul is very clear on the rules and (a bid for Euro 2020) would go contrary to an Olympic bid.
"I think it's very clear we are just for the Olympic Games. There is no other agenda, this is our number one agenda and that's what we will tell the evaluation committee."
Turkey had initially been favoured to host Euro 2020 alone, which would have seriously undermined its case for hosting the Olympics, but UEFA's decision to make it a Europe-wide tournament was a major boost for the Games bid.
Madrid and Tokyo are the other candidate cities bidding to host the 2020 Olympics.