By Dan Rivers: ITV News Correspondent

They call it “favela pacification”. Translation: sending thousands of combat troops into the toughest neighbourhoods in Rio to ensure gang violence is contained.

Officially the "pacification" is nothing to do with the World Cup.

Coincidence then that the operation we filmed in Mare finishes at the end of July, just after the tournament concludes.

We’re taken in by Captain Blanco, who tells us there are three gangs involved in a turf war in the area, but since his men have deployed it has become safer; but not that safe.

We’re still advised to wear flak jackets, since the drug dealers are as well armed as the troops. For most criminals here a machine gun comes as standard.

We see the gang’s graffiti tags marking their turf and then find a burning car set ablaze by feuding dealers.

A civil guard officer stands by watching the scene with a nonchalance that is at odds with the risk of the fuel tank exploding.

Drug dealers mark their territory in Mare, where troops will be until the end of July. Credit: ITV News

But it’s not just in Mare that this seamy underworld exists; it’s found in pockets across the city, in places just a few hundred metres from where players and fans are staying.

But Rio’s terrible reputation for violent street crime isn’t the only challenge facing organisers of this tournament.

The World Cup here should be a celebration of football, in the country that loves the beautiful game like no other. Instead the event has become deeply political.

Local people in Santa Luzia taking part in nationwide protests on May 30 against the lack of benefit they feel from the World Cup. Credit: Reuters

A large coalition of left wing protesters is furious at the lavish spending on sport, instead of basic services they say the government has failed to deliver.

In many parts of Rio graffiti lambasts Fifa, “more education, less corruption” reads one mural.

The country famous for loving football has been further divided by hosting the tournament. Credit: ITV News

There have been angry protests against the World Cup across the country in recent months, orchestrated by a shadowy collective of anarchists and left wing opponents of the government, known as the black block.

In Sao Paulo, a bitter transport strike has added to the sense of a tournament under siege, with one of south America’s most congested cities brought to a standstill by the walkout.

Read: San Paulo in total gridlock after 'open end' subway strikes

Add in the unfinished upgrading of some stadia, promised infrastructure improvements which have not yet been delivered and corruption allegations connected to the 2022 World Cup in Qatar, you can see why Fifa should expect some tough questions during its congress this week…and why it will probably do everything it can to avoid answering them.

Read more: Major sponsors 'urge Fifa to investigate Qatar 2022 bid'