Twelve men were arrested early this morning in a major national counter-terrorism operation, police said today.
The men - five from Cardiff, four from Stoke-on-Trent and three from London - were detained on suspicion of the commission, preparation or instigation of an act of terrorism in the UK.
The suspects, aged between 17 and 28, were detained by unarmed officers at approximately 5am.It is understood that the plans for the alleged attacks were at an advanced stage and involved 'multiple' locations.Raids: Police officers stand outside a house in Stoke-on-Trent, one of several raided in England and Wales during the 5am operation
West Midlands Police said in a statement: 'All were arrested at or near their home addresses, with the exception of one suspect from Stoke who was at a domestic property in Birmingham.
'Searches are now being conducted at the home addresses, plus the address in Birmingham and another residence in London.
'The suspects will be held at police stations in central London, the North West and the West Midlands.'The police statement said five of the suspects were from Cardiff, four were from Stoke-on-Trent and three were from London, including the 17-year-old.Operation: Search teams examine the garden of a house in Stoke-on-Trent
The operation is being led by Metropolitan Police Deputy Assistant Commissioner Stuart Osborne, the Senior National Co-ordinator Terrorist Investigations, and is being coordinated from the West Midlands Counter-Terrorism Unit.
It also involves the Metropolitan Police's Counter Terrorism Command, South Wales Police and Staffordshire Police, a spokesman said.Metropolitan Police Assistant Commissioner John Yates, national lead for counter-terrorism policing, said: 'This is a large scale, pre-planned and intelligence-led operation involving several forces.'Intelligence-led': John Yates, Assistant Commissioner of the Metropolitan Police
'The operation is in its early stages so we are unable to go into detail at this time about the suspected offences.
'However, I believe it was necessary at this time to take action in order to ensure public safety.'
Home Secretary Theresa May was fully briefed on the raids before they took place, the Home Office confirmed.
The arrests come after intelligence agencies in Europe, Pakistan and the U.S. intercepted a credible Islamic plot to launch raids on European cities, in a similar style to the attacks in Mumbai, India, two years ago.
More than 170 people were killed during a 24-hour co-ordinated attack on Mumbai, also known as Bombay, by 10 gunmen in November 2008. It has been blamed on Pakistani militants.
The planned attack in September would reportedly have been similar to the deadly commando-style raids in Mumbai, with other European cities, in France and Germany, also targeted.
It led Mrs May to back a warning by the United States for its citizens to be vigilant when visiting Europe.
Mrs May said the message was 'consistent' with the UK's view of the threat that existed.
She also urged the British public to report any suspicious activity as police and security services try to disrupt terrorist activity.
Advice issued by the State Department in the U.S. stopped short of recommending that citizens stay away from high-profile sites in Europe, but noted in particular "the potential for terrorists to attack public transportation systems and other tourist infrastructure".
The UK's terror threat rating remains at 'severe', the second-highest rating, meaning a terrorist attack is highly likely.But it is not known whether the drone attacks were related specifically to the plot that European authorities said they had intercepted.Arrests: Of the 12 men held, five were from Cardiff, four were from Stoke-on-Trent and three were from LondonSince the 9/11 terror attacks in the U.S. nine years ago, Al Qaeda is believed to have moved outside Afghanistan and Pakistan to other countries such as Somalia and Yemen.
Intelligence officials in Washington said a recent surge of missile strikes by unmanned US drones in Pakistan were aimed at disrupting suspected terrorist plots targeting Europe.
Police in Germany, Holland and Belgium last month arrested 10 men on suspicion of planning a terror attack.
Police are asking anyone with information that may assist the investigation to call the confidential Anti-Terrorist Hotline on 0800 789 321.