Al-Qaeda militants in Syria are plotting attacks to inflict mass casualties in the West, possibly against transport systems or "iconic targets," the head of Britain's MI5 Security Service said, Al Arabia reported.
Speaking after gunmen killed 12 people in an assault on a French satirical newspaper, MI5 boss Andrew Parker warned a strike on the United Kingdom was highly likely.
"A group of core al-Qaeda terrorists in Syria is planning mass casualty attacks against the West," Director General Parker said in a rare public speech at MI5 headquarters in London. His last public speech was in October 2013.
In the speech, planned before the killings in Paris, Parker said seasoned al Qaeda militants in Syria aimed to "cause large-scale loss of life, often by attacking transport systems or iconic targets" in the West.
Al-Qaeda killed nearly 3,000 people by attacking the United States with hijacked passenger planes on September 11, 2001. Militants inspired by the group killed 52 commuters in London on July 7, 2005 with suicide bombs.
Al-Qaeda's leader Osama bin Laden was killed by U.S. special forces in 2011, and the threat posed by the network to the West seemed to recede in recent years.
But spies in Europe and the United States have been troubled that al-Qaeda militants from Pakistan have appeared in wartorn Syria, in what some intelligence analysts say could be part of a plot to mount a major attack against the West.
Thursday's stark warning from one of the West's most influential spymasters mirrors a growing concern among Western political leaders and their Arab allies about the threat from the cauldron of militant groups in Syria and Iraq.