"The danger posed by international terrorism has grown by far due to possible use of WMDs in terrorist attacks," Mr. Patrushev told the conference of secret service leaders in Novosibirsk.
According to Mr. Patrushev, the threat of terrorists laying their hands on WMDs highlights the need for all nations, first of all, their law enforcement agencies, to pool their efforts.
Director Patrushev noted that intelligence available indicated that terrorism was becoming a transnational phenomenon.
"The spike of terrorism in Iraq, Israel, Spain, Russia and several other countries proves terrorism is a greatest threat to vital interests of a person, society and the world," he said.
According to Mr. Patrushev, terrorist attacks are becoming ever more shrewd and cruel.
"This is proven by terrorists' seizure of the school and murdering the children there in Beslan in 2004," he said.
The FSB director believes international terrorism keeps on adapting to new realities despite the hard blows dealt to it.
"Struck hard, international terrorist organizations recruit new followers, obtain new gear and coordinate their tactics to adapt to the fluid situation," he said.
Proceeds from drug trade are the main source of the money to stoke terrorism.
"No doubt, one of the main source of funding of terrorism is the money earned from drug trafficking," Mr. Patrushev said, emphasizing that the production of drugs in Afghanistan and smuggling them to other countries are run by international criminal syndicates linked with terrorists. Drug trafficking has become a serious adversary enjoying huge financial and technical capabilities.
Mr. Patrushev also stressed that the fight on terrorism should be waged within the confines of international law.
"As a proactive participant in the fight against terrorism, Russia believes the problem should be resolved based on international law and through bolstering the US's role in coordinating the struggle," he said.
Mr. Patrushev also stressed that representatives of the United Nations - UN Security Council's Counter Terrorism Committee Chairman Andrei Denisov and Executive Director Xavier Ruperez - have for the first time joined the special services' chiefs' conference.