A crime-plagued, cash-strapped Rio de Janeiro on Tuesday enters the one-month countdown to becoming the first South American city to host the Olympics.

Stadiums are all ready -- barring finishing touches -- and within weeks, Brazil expects to greet at least 500,000 tourists for the August 5-21 Games.

The mayor, Eduardo Paes, and Brazil's Olympic committee boss Carlos Nuzman were to give a news conference marking the milestone in Rio's epic effort to transform from a beautiful but crumbling city to glittering stage for the world's most-watched event.

"The city is 100 percent ready. It's an unbelievable city. I'm very proud of our city," Paes said Monday at the presentation of a new bus expressway, part of an overhaul to the overburdened transportation system.

Some 10,000 athletes will compete over 19 days in Rio, ranging from familiar sports icons such as sprinter Usain Bolt and swimmer Michael Phelps to the stars of Olympic newbie sport rugby sevens and golf, which returns after more than a century's absence.

But despite growing excitement in the sporting world and the visible transformation of Olympic sites in Rio, a mounting series of problems are overshadowing the Games.

- Security nightmare -

The authorities will deploy 85,000 police backed by soldiers on Rio's streets. That's twice as many as used in the 2012 London Olympics.

Terrorism is a serious concern after the Islamic State group demonstrated its geographical reach, with bombings in Istanbul and Baghdad blamed on the group in the last few days.

Brazil's distance from jihadist hot spots, coupled with the country's absence from wars, is expected to be the main factor on security forces' side.

However, Rio already faces its own serious violent crime that has embarrassed Olympic organizers trying to change the city's image.

Although down from horrific levels a decade ago, the murder rate is on the rise and street crime is also proliferating, symbolized by the hijacking of a truck filled with German television equipment last week.

Police -- heavily criticized by human rights groups over their brutal tactics in slums known as favelas -- are themselves coming under deadly fire. More than 50 Rio state police have been killed this year.

On Monday, some 100 officers protested in the arrivals hall of Rio's main international airport holding banners reading "Welcome to Hell" to demand unpaid salaries and overtime pay.

"We are here to show citizens and tourists from abroad the realities of Brazil," said veteran police officer Alexander Neto, 56. "They've been conned and we, too, have been conned. You have to understand there is no public security."

Rio state, which is near bankruptcy amid Brazil's crippling recession, says those late payments to the emergency services, hospitals and others are now beginning thanks to an emergency federal bailout.

- Fighting back -

The mayor and Olympic organizers have been fighting back against a torrent of bad publicity.

Despite the decision of several athletes, notably high profile golfers, to pull out of the Olympics because of fear over the mosquito-transmitted Zika virus, the authorities insist there are no serious health risks.

Zika can trigger birth defects in babies born to infected mothers, but in most cases causes little beyond flu-like symptoms -- and August is a month with few mosquitoes.

On the security issue, although Paes acknowledges problems, he blames the state government, not the city.

"This is the most serious issue in Rio and the state is doing a terrible, horrible job," he told CNN.

Paes has been unable to hide his mounting frustration with the bad publicity, also stoked last week by the discovery of unidentified human body parts on Copacabana beach, home to the beach volleyball arena.

Over the weekend, he lambasted a New York Times opinion piece that predicted a "catastrophe."

He lashed out at critics again on Monday, saying: "We can't allow this permanent aggression to continue."

He is unlikely to get his wish.

Among other events planned for the one-month countdown Tuesday was a demonstration by leftist movements protesting against "the exclusion Olympics."

"They have money for a mega-event," they said in a statement, "while delaying salaries for workers and cutting basic services for the people."

Source; AFP