Brazilian President Dilma Rousseff says the construction or renovation of nine of the 12 stadiums that will host games of the 2014 World Cup will be concluded next year.

Rousseff says in her weekly column published Tuesday that work on the stadiums is proceeding at an ''adequate pace.''

She says that nine stadiums will be ready by December 2012. She says the other three will ready one year later.

The slow pace of stadium construction or renovation is one of the main concerns as Brazil prepares for the World Cup, along with the lack of airport infrastructure.

Rousseff says that airports in six cities that will host World Cup games are being expanded and that the bidding process for the renovation of another five airports in under way.