Paris and Los Angeles delegations met with Olympic chiefs in Denmark on Monday as the race to stage the 2024 Games enters its final phase.
The 2024 rivals held talks with International Olympic Committee vice-presidents ahead of presenting their bids to international federations on Tuesday.
High on the agenda was the IOC's review into the Games designation process, which could see both the 2024 and 2028 Olympics awarded at the same crunch vote in Lima in September.
The IOC is exploring the option in order to capitalise on the Paris and Los Angeles bids at a time when fewer and fewer cities are willing to take on the financial and logistical responsibilities of staging an Olympic Games.
Both Paris and Los Angeles emphasis they are focused on 2024, whilst at the same time offering support to the IOC's review.
After talks with the mayors of both cities the IOC announced in a statement: "During the meetings with the IOC vice-presidents, the discussions focused on the 2024 Candidature Process as it heads into the final phase, six months before the election of the host city in September 2017."
The statement added that Paris and Los Angeles were told that an IOC review "may consider changes to the 2024/2028 selection process".
After its meeting, the Los Angeles delegation led by Mayor Eric Garcetti commented: "We remain committed to bidding for the 2024 Games and look forward to future discussions with the IOC Working Group as the bid progresses."
His Paris counterpart, Anne Hidalgo, said: "Paris lends its support to the IOC to review the designation process for candidate cities."
The IOC review is "interesting and legitimate," she added. "We are going to accompany the IOC in this process."
Paris 2024 co-president Tony Estanguet gave his support for the review, but the former Olympic canoeist issued a reminder that "Paris continues to remain concentrated on 2024 because we think Paris is the best place to organise the 2024 Games".
"Any change must have the complete backing of all the partners," IOC vice-president Juan Antonio Samaranch Junior stressed.
"We haven't formulated any proposal and we haven't entered into the detail of a change to the existing rules concerning 2024 at all," added the son of the former Olympic chief.
On Tuesday, both cities will present their bids to international federations assembled in Aarhus for the SportAccord convention.