LONDON (AP) — When Boston's troubled bid for the 2024 Olympics collapsed in late July, IOC President Thomas Bach made it pointedly clear he was counting on the U.S. to come up with another candidate.

Bach said the U.S. Olympic Committee had given the IOC a "commitment" to submit a 2024 bid and he fully expected the Americans to deliver a new nominee by the Sept. 15 deadline.

Message received.

With the Boston debacle in the rear-view mirror, the USOC is moving forward with two-time host Los Angeles as its bid city.

The bid was officially launched Tuesday after approval by the Los Angeles City Council, giving the USOC a fresh slate to try to bring the Summer Games back to the U.S. for the first time in 28 years.

The American bid team is wasting no time in getting the campaign started. Los Angeles Mayor Eric Garcetti, bid chairman Casey Wasserman, USOC chairman Larry Probst and CEO Scott Blackmun were traveling to Switzerland on Wednesday and will meet with Bach and other International Olympic Committee officials on Thursday at IOC headquarters in Lausanne.

The visit is part of the new "invitation phase" that allows candidate cities and the IOC to review bid plans ahead of the formal campaign. Boston and USOC leaders went through the same process a few months ago before the bid was dropped amid a lack of public and political support.

The Los Angeles bid is welcome news for Bach and the IOC, eager for a strong U.S. contender and a competitive international field. That's especially the case following the race for the 2022 Winter Games, which ended up with just two candidates after the withdrawal of four cities for financial or political reasons. Beijing defeated Almaty, Kazakhstan, in the July 31 vote.

Los Angeles joins a field that includes Paris; Rome; Hamburg, Germany; and Budapest, Hungary. Hamburg's bid faces a local referendum on Nov. 29.

Toronto, which hosted the Pan American Games in July, had also been considering a bid but appears to have cooled on the idea. The head of the city's budget committee, Gary Crawford, said Tuesday there were "a lot of unanswered questions" over financing of the games.

There has also been no word from Baku, Azerbaijan, which was mulling a bid after hosting the inaugural European Games in June.

The IOC will select the host city in September 2017. Under a new format, there will be no cut-down of the field this time and all bid cities will go to the final vote.

Some things to know about the 2024 race:

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THREE-TIME HOSTS

Both Los Angeles and Paris are bidding to host the Olympics for a third time. Los Angeles staged the games in 1932 and 1984; Paris in 1900 and 1924. London is the only city which has been a three-time Olympic host (1908, 1948 and 2012).

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LOS ANGELES' LOSING STREAK

The 2024 contest gives Los Angeles a chance to win a contested bid election for the first time. The city was the only candidate for '32 and '84, and is 0-7 in contested elections — losing out for the games of 1924, 1928, 1948, 1952, 1956, 1976 and 1980.

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WHY LOS ANGELES?

After stinging defeats for New York and Chicago for the 2012 and 2016 Olympics, respectively, Los Angeles should offer a potent case for taking the Summer Games back to the U.S. for the first time since Atlanta held the 1996 Olympics.

The 1984 Games, run by Peter Ueberroth, produced a $250 million surplus and provided a model for commercial financing of the Olympics. Bid organizers say they are confident of posting another surplus in 2024 on an operating budget of $4.5 billion.

Los Angeles says it has 85 percent of proposed venues (including the Memorial Coliseum) in place or already planned, regardless if the city gets the games. This plays into Bach's "Olympic Agenda 2020" program, which seeks affordable games and maximum use of existing or temporary venues.

The mayor, Garcetti, should be an influential figure in the international campaign as the city presents itself to the IOC as a completely new face rather than a been-there, done-that version.

At the same time, the city must dispel any concerns at home over financial risks and the financing of the Olympic Village.

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FRENCH FAVORITE

Paris has been seen as an early front-runner with a well-organized bid campaign that secured the buy-in from athletes and the city and national government.

On Wednesday, the French Olympic Committee launched a promotion campaign dubbed (hashtag)JeReveDesJeux (I dream of the games). Wristbands with the slogan will be put on sale to help back the Paris bid.