Official estimates of the size and influence of the Russian mafia make frightening reading - the unofficial estimates are terrifying.

In 1994 Russia's then interior minister, Mikhail Yegorov, said the number of organised crime groups in the former Soviet Union had grown from 785 during Gorbachev's reign to 5,691.

By 1996 this estimate had grown to 8,000 groups, each with memberships of between 50 and 1,000.

The government in Moscow estimates the Russian mafia controls 40% of private business and 60% of state-owned companies.

Russian mafia tried to sell this old Soviet sub to a Colombian drugs cartel

Unofficial sources say 80% of Russian banks are controlled either directly or indirectly by criminals.

Mafia is not new

The Russian mafia is not a new phenomenon but its rapid growth and increasing willingness to use extreme violence is worrying law enforcement officers worldwide.

Criminals began to thrive during the Brezhnev era when the Soviet economy was stagnating.

Crooks known as "thieves in law" (vory y zakone) began to fill the gap, supplying luxuries such as jeans, cigarettes, vodka, chewing gum and hi-fi equipment to those who could afford them.

The Soviet-era gangsters kept a low profile, knowing all too well they would end up in the gulags if they flaunted their ill-gotten wealth.

Moving in after the fall of communism

The downfall of communism left an economic, moral and social vacuum which the mafia has been only too happy to fill.

Hundreds of ex-KGB men and veterans of the Afghan war veterans offered their skills to the crime bosses.

The mafia also provided money and jobs to young men in Moscow, St Petersburg and Kiev who were struggling to cope following the collapse of the communist safety net.

Early on, in 1989, the octopus began reaching its tentacles outwards across Europe and America.

Russian emigre communities in New York's Brighton Beach district, in Israel, Paris and London were seeded with mafia spawn.

Brighton Beach is the home of the Russian mafia in America

Billions of dollars laundered

It is estimated around £16bn ($25bn) of dirty Russian money has left the country since the fall of communism - most of which has been laundered by banks in Switzerland, Liechtenstein and Cyprus.

Another favourite target is Israel. Many Russian gangsters claim to be of Jewish origin, in order to get an Israeli passport. The Russian mafia is said to have poured £2.5bn ($4bn) into the Israeli economy.

Further afield the mafia is accused of running prostitution and gambling rings in Sri Lanka and of conniving with the Colombian drugs cartel.

One Russian gang tried to sell their new-found Colombian friends a Soviet-era submarine which would have enabled them to smuggle drugs into the United States easier.

Links with other organised crime groups threaten to create a Vorovski Mir (Thieves' World).

Threat to US national security

Louis Freeh, head of the American Federal Bureau of Investigation (FBI), said recently the Russian mafia was the greatest threat to US national security although he later withdrew this comment.

Louis Freeh: 'They pose a serious threat to the countries they operate in.'

In 1995 an FBI document stated: "If Russian organised crime could help foreign crime networks to gain access to nuclear material or other fissile weapons then the scenario becomes truly frightening."

Back at home the mafia's control of the economy appears to be stifling foreign investment.

The German interior minister claimed recently foreign companies based in Russia routinely pay up to 20% of their profits to the mafia.

This level of extortion may explain why per capita investment in Russia is only a seventh of what it is in neighbouring Poland, which has its own, but less serious organised crime problem.

Thousands of shootings

Russia sees around 10,000 fatal shootings a year, 600 of which are contract killings. In the last five years 95 bankers have been murdered.

Assassins, who often kill for as little as £600 ($1,000), have targeted hotel bosses, restaurateurs, sports figures, businessmen, politicians, journalists and Afghan war veterans.

In Soviet times the KGB kept the lid on the Russian mafia but its successor, the FSB, is under-funded and demoralised.

While the police's elite Berkut (Eagle) force conduct frequent high-profile commando-style raids they appear to be catching only the small fry.

Russia appears to be fighting a losing battle against the mafia.

• So who are the Russian mafia?
• How Russia's mafia is taking over the Israeli underworld