MI5 chief Andrew Parker in warning over 'increasingly aggressive' Russia

Russia has become "increasingly aggressive" in pursuing its foreign policy goals and is “at work across Europe and in the UK today”, the head of MI5 has warned.

Andrew Parker, the Security Service's director general, said Russia had been a "covert threat" for decades but there were now more methods available for its agents to use.

These include propaganda, spying and cyberattacks, he said.

Mr Parker added that at a time when much of the focus was on Islamic extremism, covert action from Russia and other countries was a growing danger.

"(Russia) is using its whole range of state organs and powers to push its foreign policy abroad in increasingly aggressive ways - involving propaganda, espionage, subversion and cyberattacks," he told The Guardian.

"Russia is at work across Europe and in the UK today. It is MI5's job to get in the way of that."

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Mr Parker said Vladimir Putin's state "increasingly seems to define itself by opposition to the West and seems to act accordingly".

He added: "You can see that on the ground with Russia's activities in Ukraine and Syria. But there is high-volume activity out of sight with the cyber threat.

"Russia has been a covert threat for decades. What's different these days is that there are more and more methods available."

The MI5 chief's comments have been dismissed by the Kremlin, which said they "do not correspond to reality".

Presidential spokesman Dmitry Peskov said: "Until someone produces proof, we will consider those statements unfounded and groundless."

Mr Parker's warning came days after Vladimir Putin accused the West of exaggerating the threat Russia poses to the world to justify increased military spending.

Mr Parker also warned about the threat posed by homegrown terrorists.

He said there were about 3,000 "violent Islamic extremists in the UK, mostly British" and that his agency would expand from 4,000 to 5,000 officers over the next five years to deal with the threat.

Earlier, Mr Parker revealed that police and intelligence services had foiled 12 terror plots in the UK since June 2013.

In comments after an address to the Royal Society's annual diversity conference, he said: "IS is an enduring threat, here to stay, and is at least a generational challenge.

"MI5 and the intelligence agencies have good defences because of the investment made in our capabilities.

"We will find and stop most attempts to attack us, but not all."

Mr Parker's remarks came as a Sky News investigation found that the resources of the security services were being stretched by the hundreds of convicted terrorists who have been freed from jail in recent years.

Many of those released have refused to take part in deradicalisation programmes while in prison.