Al-Qaeda-linked extremists are planning attacks intended to cause mass casualties in the UK, a top British intelligence report has warned.
The report, which has been prepared by the intelligence branch of the British Ministry of Defence, MI5 and Special Branch, warned that secret cells of al-Qaeda extremists based in London, Birmingham and Luton are planning attacks in the UK.
The so-called Government Security Zone (GSZ), an area, which covers the Houses of Parliament, Whitehall, Buckingham and St James' Palaces, is a possible target of the al-Qaeda cells, with threat level in the GSZ described as "severe", the Daily Telegraph reported.
"For the foreseeable future the UK will continue to be a high-priority target for international terrorists aligned with al-Qaeda. It will face a threat from British nationals, including Muslim converts, and UK-based foreign terrorists, as well as terrorists planning attacks from abroad," the top intelligence report said.
According to the British daily, the report headlined 'International Terrorism' states that "some thousands" of extremists, many believed to have been trained in overseas terrorist camps, are active in the UK.
"The majority of extremists are British nationals of south Asian, mainly Pakistani origin but there are also extremists from north and east Africa, Iraq and the Middle East, and a number of converts," it warned.