Platini said progress was "neither uniform nor constant"

Poland and Ukraine will remain as Euro 2012 co-hosts but have been warned to improve their infrastructure ahead of the tournament.

There had been concerns that hosts had fallen behind with their preparations.

The governing body's president Michel Platini said: "Both host countries must continue to make the necessary efforts.

"Any slackening could put in doubt the organisation of this tournament in these countries. Warsaw and Kiev are the key issues."

Uefa held an inspection over the summer on the suitability of stadiums and infrastructure and although the report was believed to be critical, Uefa's executive committee said its decision to award the event to the former Eastern bloc nations was final.

"It's not about the stadia, it's about the infrastructure, hotels and transport," added Platini.

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"We were promised new airports and we will not have new airports, we were promised new roads and we are still waiting.

"We cannot organise a European competition if the capitals are not participating."

Poland and Ukraine, who were awarded the competition in April 2007, had admitted earlier this year that preparations had fallen behind because of political instability in both countries.

However, with new governments elected at the end of last year, preparations have progressed over the last six months although, according to Platini, it was "neither uniform nor constant".