Counterintelligence efforts against Russian and Chinese agents attempting to steal British military and civilian technology secrets are diverting much-needed resources from MI5's antiterrorism operations, according to MI5 director Jonathan Evans. Speaking at the Society of Editors' annual conference in Manchester on Monday, the internal espionage chief warned that efforts to tackle terrorism were being stalled by work to halt foreign intelligence agents from stealing sensitive information on civilian and military technology. He singled out agents from Russia and China for espionage activities. Evans specifically warned about the number of Russian spies in the UK, saying there had been high levels of covert activity by foreign intelligence organizations in Britain this year. "Since the end of the Cold War we have seen no decrease in the numbers of undeclared Russian intelligence officers in the UK, at the Russian Embassy and associated organizations, conducting covert activity in this country," he said. Evans said he was disappointed that MI5 had to divert resources to combat foreign intelligence threats instead of using them to fight the global danger of terrorism. About 2,000 people, some as young as 15 years old, are involved in terrorist activity in the UK, according to the new head of Britain's MI5 security service. A year ago MI5 identified about 1,600 people who posed a "direct threat to national security and public safety," Evans said, and that the figure would be "at least 2,000 today." The growth is partly due to extended coverage of extremist networks, he said, but "also because there remains a steady flow of new recruits to the extremist cause." "As I speak, terrorists are targeting young people and children in this country," Evans said. "They are radicalizing, indoctrinating and grooming young, vulnerable people to carry out acts of terrorism." The UK had to do more to protect these young people, he added. Referring to the spate of planned and perpetrated attacks on the UK in the past few years, Evans said they were "not simply random plots by disparate and fragmented groups," but part of a "deliberate campaign" by al-Qaida. "Al-Qaida has a clear determination to mount terrorist attacks against the UK," he said. "This remains the case today, and there is no sign of it reducing." In the past 12 months, MI5 has found links between terrorist plots in the UK and an increasing number of countries, Evans said. The "al-Qaida brand," in places like Iraq, Algeria and parts of East Africa, especially Somalia, had expanded and now posed a threat to the UK, he said. "The more this ideology spreads in our communities, the harder it will be to maintain the kind of society that the vast majority of us wish to live in," Evans said, referring to the growing threat of Islamic extremism, which he called "the most immediate and acute peacetime threat" in the 98-year history of MI5. Testimony from a US terrorist-turned-witness in British court cases has revealed how young Britons are trained for attacks at terrorist camps in tribal areas of Pakistan. Though Pakistan remained a key training ground for Britons, Evans said, similar centers were emerging elsewhere. Terrorist activity was also increasing across Europe, he said, citing recent arrests of suspects in Germany, Denmark and Austria. Evans said work by his agents alone to thwart plots would not be enough to stop the threat of extremist terrorism. He called for greater efforts from the government and society to counter the message of radical preachers. "If we only react tactically while our enemies plan strategically, we shall be hard put to win this," Evans said. "A key part of our strategy must be perseverance. It starts with rejection of the violent extremist ideology across society." AP contributed to this report.