UEFA president Michel Platini issued his strongest warning yet to Euro 2012 co-hosts Poland and Ukraine on Saturday, saying the tournament would not be staged there if stadiums in their capital cities were not ready.
Platini, who did not give a deadline for the stadiums, will lead a 12-man delegation to the two countries next week to examine the progress being made.
Speaking to a packed news conference in Vienna on the eve of the Euro 2008 final between Spain and Germany, Platini said: "We will do everything we can to hold it in Poland and Ukraine.
"There is no back-up plan. We have not had any second thoughts, or other thoughts and we respect our decision to go to Poland and Ukraine.
"The only thing that will make me decide not to go is if there are no stadiums in the capitals of Warsaw and Kiev. If there are no stadiums, there will be no tournament."
UEFA warned Poland and Ukraine after January's executive committee meeting in Zagreb that the months to come would be decisive in determining whether the countries were in a position to host the finals.
Platini said on Saturday that UEFA would make its final decision at its executive meeting in Bordeaux on Sept. 25-26.
Infrastructure problems including the modernisation of airports and road and rail networks, the construction of new hotels and the stadium plans have all plagued the project.
Building work at the Olympic Stadium in Kiev, which is due to host the final in 2012, has been further complicated because of the planned demolition of a shopping centre near the stadium.
On Wednesday, Ukraine's sports minister Yuri Pavlenko said two companies were vying for the right to renovate the stadium in Kiev.
Eight venues are due to stage games, four in each country. As well as Warsaw, the Polish venues are Poznan, Wroclaw and Gdansk. Ukraine's four venues are Kiev, Donetsk, Lvov and Dnipropetrovsk.
UEFA awarded the tournament to Poland and Ukraine in April last year, ahead of rival bids from Italy and a joint bid from Croatia and Hungary.