BUDAPEST (Reuters) - Budapest could decide as soon as next week whether to withdraw its bid to hold the 2024 Olympic Games, the Hungarian capital’s mayor said on Friday, in another blow to organizers’ attempts to find a host city.

Andras Fekete-Gyor Leader of political movement Momentum holds up one of the boxes containing over 266,000 signatures of Budapest voters who want a referendum on Budapest's bid to host the 2024 Summer Olympics in Budapest, Hungary, February 17, 2017. REUTERS/Laszlo Balogh

Hamburg, Rome and Boston have already abandoned their bids to host the Games, an event, whose costs have risen sharply over the past 20 years. If Budapest pulls out, that would leave only Paris and Los Angeles still in the race.

Prospects of a successful bid dimmed after a local political movement, Momentum, gathered enough signatures to force a referendum on the matter, which has grown increasingly unpopular among Hungarians according to a recent opinion poll.

Budapest Mayor Istvan Tarlos told a news conference that if a referendum was called, he would “seriously consider” a proposal to withdraw the bid.

If Prime Minister Viktor Orban and the Hungarian Olympic Committee supported a withdrawal, he would submit a motion to that effect to the city council on Wednesday, the local news website index.hu quoted Tarlos as saying.

Orban and Tarlos will meet to make a decision on Thursday at the latest, after government and the city assembly meetings to discuss the situation the previous day, the national news agency MTI said, quoting a joint statement from the mayor’s office and Orban’s media chief, Bertalan Havasi.

Momentum, launched by a group of students born around 1989 when the Communist regime collapsed, said it had collected more than 266,000 signatures on a petition against the bid within a month, which its leader said would be enough to trigger a vote.

“The past 30 days have been one of the most magnificent periods in the history of democracy in Budapest,” Andras Fekete-Gyor told journalists after announcing the petition result.

“It would be really cowardly on their part if (Orban and Tarlos) made the referendum impossible or if they withdrew the bid before calling a referendum,” he said. “This would be not only cowardice but also betrayal.”

There was no immediate comment from bid organizers or city hall, but Orban’s Fidesz party appeared to distance itself from the bid. Lajos Kosa, a senior Fidesz lawmaker, said the issue did not come up at a party meeting and was in the city’s hands.

“This is a national process and the IOC will not comment at this stage,” an International Olympic Committee spokesperson said.

The Budapest Election Office must now rule whether enough valid signatures - 10 percent of Budapest’s roughly 1.4 million voters - have been collected to call a referendum.

‘THE WISHES OF THE PEOPLE’

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The International Olympic Committee is due to announce the 2024 host city in September. If Budapest won, Hungary would become the first Eastern European country to welcome the Summer Games in the post-Communist era..

Hamburg pulled out after a negative referendum result in 2015, while Rome Mayor Virginia Raggi ended her city’s bid last year to honor an election promise.

A Zavecz Research institute poll published last week showed 51.95 percent of Budapest citizens would vote against the Olympics, up from 31.7 percent in September.

Orban’s chief of staff Janos Lazar said on Thursday the government would await the outcome of the referendum initiative. “The wishes of the people will be respected,” he said.

Momentum, with support from leftist and opposition parties, advocates spending the huge budget for the Games on sectors including healthcare and education.

If Budapest rejects the Games, this would deal an unexpected blow to Orban’s Olympic dreams and a boost for Momentum, which plans to turn itself into a political party next month.

Hungary will hold parliamentary elections in April 2018 and Momentum will broaden its focus to address other public issues once it becomes a party, its leader Fekete-Gyor has said.