FIFA secretary general Jerome Valcke has apologised to the Brazilian government for his outspoken criticism of delays in their 2014 World Cup preparations but stressed there is still "an air of concern" at the lack of pace.

Valcke last week issued a warning to 2014 organisers saying "you have to push yourself, kick your a*** and just deliver this World Cup". In an interview in Surrey with four media organisations, including the Press Association, Valcke also warned of looming transport and accommodation problems for fans at the tournament.

That provoked a furious response from Brazil's sports minister Aldo Rebelo, leading to a climbdown from Valcke, who has sent a letter to the minister saying there had been "a misinterpretation in the translation of his words" into Portuguese. The letter adds: "I would therefore like to apologise to you and anyone who was shocked by my words."

He adds: "There is certainly an air of concern at FIFA and as the person who is ultimately responsible for delivering the World Cup I am under quite some pressure.

"The World Cup is the key to our entire system."

Valcke added that he was confident the problems were not insurmountable and reiterated FIFA would not consider any other option to Brazil for the 2014 World Cup.

Rebelo said at the weekend the Brazilian government no longer wanted to deal with Valcke due to his comments.

Valcke responded on Saturday saying that was "puerile".

He added: "If that's the problem because nothing has happened over the five years [and] I made, wow, one comment saying things are not working well and I for once say exactly what is happening in Brazil.

"If the result is they don't want to talk to me any more, I'm not the guy they want to work with, that's a bit puerile."