LONDON, Jan. 9 (UPI) -- The director general of MI5, Andrew Parker, said there are "mass casualty attacks against the West" being planned by "a group of core al-Qaida terrorists in Syria."
In a rare public speech by Britain's domestic intelligence chief at the agency's headquarters in London on Thursday, Parker addressed the terror challenges facing the U.K. in 2015.
Attacks are often directed at "transport systems or iconic targets," he said before adding that "we know, for example, that a group of core al-Qaida terrorists in Syria is planning mass casualty attacks against the West."
Parker was believed to be referring to the Khorasan Group, comprised of veteran al-Qaida members.
The U.S. initiated airstrikes against the Khorasan Group on Sept. 22 based on intelligence assessments that the group was planning an imminent attack in the U.S. or Europe.
MI5's focus is increasingly on Syria, Parker noted, pointing out that "a significant proportion" of Britons, "around 600," who traveled there have joined the Islamic State.
"It was primarily the rising threat from Syria -- not just ISIL -- that led the Joint Terrorism Analysis Centre to raise the threat level for international terrorism from 'substantial' to 'severe' last summer. 'Severe' is an evidence-based judgement meaning that an attack on the U.K. is highly likely."
Parker explained that IS poses a three-pronged threat to Britain: 1) British citizens have been targeted and murdered in the Syria region; 2) violent extremists in Britain are being encouraged to launch attacks from inside the country; and 3) IS propaganda seeks to provoke individuals in the U.K. into carrying out attacks in Britain.
"We know that we cannot hope to stop everything," Parker acknowledged, but said that security services such as MI5 would try their best. He revealed that three U.K. terror plots were foiled recently.