Organized Central European cybercrime gangs are a security threat to the United States and have been targeted in a new U.S. strategy released this week.

U.S. President Barack Obama unveiled his Strategy to Combat Transnational Organized Crime Monday at the White House, warning that international criminals have "taken advantage of our increasingly interconnected world to expand their illicit enterprises."

Targeting cybercrime is high on the strategy list because, the document says, it "undermines worldwide confidence in the international financial system.

"Through cybercrime, transnational criminal organizations pose a significant threat to financial and trust systems -- banking, stock markets, e-currency and value and credit card services on which the world economy depends."

Obama said cybercriminals are receiving protection in their home countries.

"These networks also threaten U.S. interests by forging alliances with corrupt elements of national governments and using the power and influence of those elements to further their criminal activities," he said, adding, that in some cases, national governments "exploit these relationships to further their interests to the detriment of the United States."

Some estimates indicate that online frauds perpetrated by Central European cybercrime networks have defrauded U.S. citizens or entities of approximately $1 billion in a single year, the report said.

Focusing more security emphasis on cybercrime is justified, it said, because computers and the Internet are involved in "most" international crime. But, the White House warned, the United States faces a "critical shortage of investigators" with the deep expertise needed to follow digital evidence trails.

Obama also used the opportunity to declare sanctions on four of the world's largest criminal gangs -- Italy's Camorra, the Japanese Yakuza, the Los Zetas of Mexico and Brothers' Circle of Russia -- imposing a freeze on all property owned by them in the United States, The Voice of America reported.

The focus on Central and Eastern Europe is well-placed, says analysts who call the countries of Central Europe, especially the Czech Republic and Hungary, major centers for powerful international crime syndicates who have managed to set up shop in the midst of the European Union.

The Flare Network, a group of European anti-crime civil societies, said in January that Hungary is a "global epicenter" of the illegal pornography industry.

The sex industry in Central Europe (including online crime as well as clubs, movies and brothels) generates $7.3 billion per year, it said.

Another ubiquitous and costly form of cybercrime frequently launched from Central Europe is "botnet" technology -- networks of computers used without their owner's knowledge for cybercrime. The "zombie" computers can be used by their controllers for such crimes as spamming and the theft of credit card information.

Botnets can also be used to carry out politically motivated cyberattacks, the EU's "cybersecurity" agency, ENISA, said in March when it studied the size of the problem and issued recommendations after consulting with computer experts.

ENISA's Giles Hogben said one of the conclusions was they botnets didn't have to be big to be dangerous.

"Size is not everything -- the number of infected machines alone is an inappropriate measure of the threat," he said.