CHICAGO (REUTERS) - Chicago has joined Vancouver in pulling out of the chance to be a host city in a joint United State-Canada-Mexico bid for the 2026 World Cup, citing uncertainty over potential costs and Fifa's inflexibility.

"Fifa could not provide a basic level of certainty on some major unknowns that put our city and taxpayers at risk," Mayor Rahm Emanuel's office said in a statement.

"The uncertainty for taxpayers, coupled with Fifa's inflexibility and unwillingness to negotiate, were clear indications that further pursuit of the bid was not in Chicago's best interests."

British Columbia had expressed similar cost concerns for Vancouver.

Chicago's Soldier Field had been one of 32 potential venues on a list released last year by the joint bid committee.

The stadium hosted the opening game and four other matches during the 1994 World Cup in the United States.

Soccer officials are expected to announce later on Thursday (March 15) the final list of potential venues for the 2026 North American bid.

Morocco is the only challenger to the joint Canada, Mexico and US bid to stage the tournament.

Fifa will vote to decide on the winning bid at its congress on June 13.