Kaspersky Lab's Alexander Gostev told a news conference that the number of malicious software programs had grown 41% year-on-year to about 60,000.
Moderately harmful trojans which cannot reproduce themselves accounted for 91% of the total, while 5% were self-replicating worms and 4% were malware.
However, "Nine major viral epidemics were detected in 2005, which is almost 50% lower than last year's figure [14]," he said.
According to Gostev, the number of viruses spreading through mobile telephones has been growing particularly rapidly in recent years.
"More than ten new viruses for mobile phones emerged last year alone. Some 186 viruses for mobiles were detected as of the end of 2006, against 106 in December 2005," he said, explaining that such viruses are designed to steal money from users' accounts.
Hackers keep coming up with new channels to target users, with instant messengers among the most recent additions, said the analyst.
"Last year viruses continued their swift expansion into Internet areas that had until recently been quite safe - such as online games and social networks."
Another Kaspersky Lab expert, Anna Vlasova, said unsolicited messages and images accounted for 70-80% of Russia's e-mail traffic in 2006.
The share of spam in mail under Russia's Web domain "stood at 55% as of January 5, 2006, and at about 80% as of December 31, 2006," she said.
Most of the spam comes to Russia from the United States and China (20% and 11%, respectively), advertising pharmaceuticals and training programs.
"Some new spam themes were added to the list last year - legal counseling and audit, real estate, and graphic design services," she said.
Criminal spam is rising steadily, Vlasova said. The share of criminal spam in the overall volume of unsolicited e-mail on Russia's internet amounted to 15%-18% in 2005, and reached 30% in 2006.
