The news was delivered as San Diego Mayor Bob Filner and his Tijuana counterpart, Carlos Bustamante, prepared to name a cross-border planning committee within the next week and unveil a logo.
Scott Blackmun, the USOC's chief executive, said Friday that the committee was talking to 10 cities about a possible bid, including San Diego-Tijuana. He said the committee hadn't looked carefully at the cross-border proposal but that it would "have its challenges."
After more research, Christopher Sullivan, the USOC's chief of protocol and bids, called Filner's liaison to the committee on Tuesday to say the International Olympic Committee charter doesn't allow for bordering countries to host Summer Games, said USOC spokesman Patrick Sandusky.
"There's no opportunity for them to bid together," Sandusky said.
Filner said he was "undaunted."
"The true spirit of the Olympics embodies my conviction that we should vigorously pursue the dream of having two countries host the Olympics in the greatest bi-national region of the world. Rules and bylaws can be changed," he said.
A spokeswoman for Bustamante, Martha Saldivar, didn't immediately respond to a message.
For Filner, the bid was part of a broader effort to build closer ties with a Mexican border city separated by an overwhelming presence of Border Patrol agents and two fences—one topped with coiled razor wire. A bid would force the cities to examine their strengths and weaknesses together and assess infrastructure in a region of about 5 million people.
"Even if we lose, we win," Filner, a former congressman who was elected to a four-year term in November, said Saturday.
Bustamante embraced the idea when Filner announced it at a ceremony in February to open a city of San Diego office in Tijuana. The Mexican leader said a bid would enhance the region's image.
It was a familiar setback. San Diego philanthropist Malin Burnham said the USOC doomed a bid he led to bring the Summer Games to San Diego-Tijuana in 2016, determining 10 years ahead of the date that there wasn't enough time to amend the IOC charter. A planning committee had raised $300,000 and hired architectural firm HOK to develop a proposal, which Filner planned to use as a starting point for the 2024 bid.
San Diego could decide to pursue a bid without Tijuana, Sandusky said.
The USOC has said it will decide by the end of 2014 whether to submit a bid. Los Angeles—host of the 1984 and 1932 Summer Games—Philadelphia and Tulsa, Okla., have also expressed interest and New York and San Francisco are possible contenders.
San Diego and Tijuana could also ask the Mexican Olympic Committee to sponsor a joint bid, but they may encounter the same hurdle they did with the USOC.
A joint bid would still face significant challenges, including a lack of sporting venues. It also often takes hours in line to enter the United States at the nations' busiest border crossing.
AP Sports Writer Stephen Wilson in London contributed to this report.