DUSHANBE, January 9, 2015, Asia-Plus – International media sources report that the head of Britain’s MI5 Security Service Andrew Parker said on Thursday that al Qaeda militants in Syria are plotting attacks to inflict mass casualties in the West, possibly against transport systems or “iconic targets.”

MI5 director general reportedly warned a strike on the United Kingdom was highly likely.

According to Reuters, Mr. Parker said in a rare public speech at MI5 headquarters in London yesterday that a group of core al Qaeda terrorists in Syria is planning mass casualty attacks against the West.

Parker said around 600 British extremists had traveled to Syria, many joining the militant group which calls itself “Islamic State” and has taken control of swathes of Iraq and Syria.

The group, an offshoot of al Qaeda, has beheaded two U.S. journalists and an American and two British aid workers in an effort to put pressure on a U.S.-led international coalition bombing its fighters in Syria.

Islamic State militants in Syria were plotting attacks on Britain and making sophisticated use of social media to incite British nationals to carry out violence, Parker said.

MI5, established in 1909 to counter German espionage ahead of World War One, had stopped three potentially deadly “terrorist plots” against the United Kingdom in recent months, he said.

“We face a very serious level of threat that is complex to combat and unlikely to abate significantly for some time,” said Parker, who has argued strongly for more surveillance powers to spy on militant communications on the Internet.

He said that the security services needed to have access to such communications.

“My sharpest concern as Director General of MI5 is the growing gap between the increasingly challenging threat and the decreasing availability of capabilities to address it,” he said.

Twitter and Facebook are so important to militants that technology giants should give security services greater access to their networks, the head of Britain’s GCHQ eavesdropping agency said last year.

“The dark places from where those who wish us harm can plot and plan are increasing,” Parker said. “We need to be able to access communications and obtain relevant data on those people when we have good reason.”