Though they still retain safe havens in Pakistan and Afghanistan, jihadists are now heading to the Middle East to seek terrorist training as parts of the Arab world have "once more become a permissive environment for al Qaeda", British intelligence chief has warned.
Terming this a "new and worrying development" that "could get worse as events unfold," MI5's Director General Jonathan Evans said in a rare public speech here as his agency braces for an array of threats ahead of next month's summer Olympics.
Warning "the (Olympic) games present an attractive target for our enemies and they will be at the centre of the world's attention in a month or so," he said that efforts have been taken to ensure that the sports extravaganza did not become an easy target.
The MI chief said Iran was another source of potential concern, as the west and Israel put pressure on Tehran to abandon any nuclear weapon ambitions it may secretly harbour, The Guardian reported.
He said there had been a series of attempted plots against Israeli interests in India and Azerbaijan, as well as a plan by Iran's Islamic Revolutionary Guard Corps to attack the Saudi ambassador in the US.
Instability in the Arab region had created "a permissive environment for al Qaeda", Evans said adding that there was evidence that Britain's "would be jihadis" were travelling in search of training and opportunities for terror activity.
Al Qaeda, he said, was shifting away from Pakistan and Afghanistan towards Yemen, Somalia and the Sahel, the MI chief said.
"We appear to be moving from a period of deep and focused threat to one where the threat is less monolithic but wider," he added.
Though Evans did not say how many people from the UK had gone to the region, it is believed the agency has monitored more than 100 who have attempted to link up with extremists in countries such as Yemen, Egypt, Syria and Libya.
Evans said one byproduct of the Arab spring was giving al Qaeda a chance to re-emerge in the countries where the network first won popular support.
In the long-term, more democracy should "ease some of the pressures that have spawned extremism in the region", he said, but in the short-term, with the Arab world in radical transition, this "more immediate problem has emerged".
"This is the completion of a cycle," said Evans. "al Qaeda first moved to Afghanistan in the 1990s due to pressure in their Arab countries of origin. They moved on to Pakistan after the fall of the Taliban. And now some are heading home to the Arab world again. And a small number of British would-be jihadis are also making their way to Arab countries to seek training and opportunities for militant activity."
The scale of terrorist ambition emerging from Yemen is believed to be at the top of MI5's worry list, and the director general made particular reference to recent plots believed to have been hatched in the country: "Repeated attempts by al Qaeda in Yemen to mount attacks on aircraft, as we have seen in the underpants bombs and the bomb found in a printer cartridge at East Midlands airport, could have caused mass civilian casualties."
He acknowledged that less than half of MI5's priority case work now involved some kind of Afghanistan or Pakistan dimension – a few years ago it accounted for 75% of the security agency's work.
"We appear to be moving from a period of a deep and focused threat to one where the threat is less monolithic," he said. As well as the potential for al Qaeda reemerging in Arab countries, Evans said some supporters of the al-Shabaab militia in Somalia "were seeking to work with al Qaeda in Yemen, and there are links across to Mali and down to west Africa, where the UK has political, economic and demographic ties".