Brazil's President Dilma Rousseff (C) signs a soccer ball as she poses for a picture during the opening ceremony of the Beira-Rio stadium, which will be one of the stadiums hosting the 2014 World Cup soccer matches, in Porto Alegre February 20, 2014.

Brazilian President Dilma Rousseff Tuesday spotlighted the government's commitment to fighting sex tourism, in the wake of two controversial T-shirts of Adidas ahead of the World Cup.

Through her Twitter account, the president said Brazil welcomes all tourists, but will "increase its efforts" against sexual exploitation, especially of children and teens.

Millions of tourists are expected to pour into Brazil next week to attend its world-renowned Carnival festivities. Millions are expected again later in the year, as Brazil hosts football's biggest competition, the FIFA World Cup, which will take place in 12 state capitals.

"The government will increase its efforts to prevent the sexual exploitation of children and adolescents during Carnival and the World Cup," the president said.

Rousseff said a special police hotline, Disk-100, was available for people who wanted to report incidents of sexual exploitation of minors, and urged people to denounce such crimes.

Rousseff's comments came amid controversy surrounding World Cup sponsor Adidas, which was reportedly selling on its US-based website promotional T-shirts linking sex and Brazil.

The incident prompted Brazil's official tourism company Embratur to release a statement earlier on Tuesday vehemently repudiating the practice.

Embratur said it is in contact with Adidas to request that the brand stop selling the shirts immediately.

"Sexual exploitation is an unacceptable crime and should not be mistaken for a type of tourism. We want to make it clear to our main partners in the tourism sector that Brazil does not tolerate this kind of crime in its territory," said Embratur president Flavio Dino.