That arguement has been made repeatively here but its basically inconclusive for the US. You might mention Washington and Detriot with cities with high crime and strict gun control laws, but I could mention cities like Dallas, Miami and Houston with cities with liberal gun laws and also high crimes rates.
As for countries, its much more the other way around. Most modern countries (most of Europe, Asia) have strict gun control laws and low gun related violence. While the worst gun related violence are in countries that DO allow the private ownership of guns (USA, Brazil).
I lived my entire life in one of the largest cities in America (NYC, which incidently enjoys low crime and strict gun laws), and I can tell you that within city limits having a gun is a bad idea. The reason is people in big cities are under stress, have low tolerence for others, and anger very quickly. Giving people guns in a city like NYC is like trying to put out a fire with gasoline.
Before the gun laws went into affect in the 1990s, I witnessed an idiot pull a gun in a dispute over who was in line first in a Burger King. There was another idiot a year ago who shot someone because he was talking on his mobile during a movie (in another city, not NY). The city is the city, not the countryside or the burbs. A stupid arguement can become deadly in a nono-second, it is simply not wise to allow normal people (not criminals) to own guns in areas where they are much more likely to use them against each other.
I believe in moderation. I have no problem with people owning guns as long as they are use some common sense about them. For example, bringing a gun to school is a univerally bad idea. I would have thought this would have been clear by now after Columbine and VA Tech, but apparently some people still dont seem to get it. The truth is the 2nd Amendment was written for a different era and is obsolete by todays standards. Society has changed since then and so have firearms. If people want to live by the 1789 interpretation of the 2nd Amendment then they'll have to go all the way and carry a flintcock and a powder horn.
The problem with the gun arguement in America is that both sides think their solution is best for eveyone. There is no one size fixes all solution. It is not accurate to say that guns cause high crime rates, but increasing gun ownership doesnt automatically lower crime rates.