by Andrew Gully
LONDON, Aug 4 (AFP) - Police were on Wednesday questioning a dozen men held after a series of raids in London and across England triggered by intelligence on "alleged international terrorism".
A 13th man arrested in north London as part of Tuesday`s raids has been released without charge, police said.
The men, aged between 19 and 32, were suspected by police of involvement in the commission, preparation or instigation of acts of terrorism.
Witnesses described on Wednesday the dramatic daylight raids, as police continued to search a number of addresses in London, central England, and the northwestern town of Blackburn.
BBC television quoted police sources as saying the suspects were "all of (south) Asian origin" and that at least some of them were thought to be British nationals.
It also said that Tuesday`s raids were "not directly linked" to a crackdown on Al-Qaeda suspects in Pakistan which prompted a heightened state of terrorist alert in the United States.
A Pakistani intelligence officer in Islamabad said on Wednesday that Britain had arrested a senior Al-Qaeda operative after a a tip-off from Pakistani investigators.
The official, speaking to AFP on condition of anonymity, could not say whether the man, identified as Abu Eisa Al Hindi, was among Tuesday`s arrests.
The 13 suspects -- all in their 20s and 30s -- were taken to a central London police station to be questioned by officers of the Metropolitan Police`s anti-terrorist branch.
"Today`s operation is part of continuing and extensive inquiries by police and the security service into alleged international terrorism," the police said in a statement on Tuesday.
On Sunday, the Home Office said Britain remained under a "real and serious" threat from terrorism, after the US authorities warned of potential truck or car bomb attacks against financial institutions in Washington and New York.
Tuesday`s arrests came as Prime Minister Tony Blair came under pressure to spell out the level of the terrorism threat in Britain.
Meanwhile, as a massive security operation continued in US cities.
The United States was put on a heightened state of alert following the seizure of computer files from Al-Qaeda suspects captured in Pakistan.
The documents apparently mention potential targets for attack both in the United States and Britain.
But while police in London are said to have spoken to branches of US banks in the British capital, security on this side of the Atlantic has not been increased by any notable degree.
The Home Office indicated only that no specific threat had been uncovered, saying: "We are maintaining a state of heightened readiness in the United Kingdom."
The raids also coincided with a request from a British parliamentary committee for Home Secretary David Blunkett to scrap draconian counter-terrorism laws passed in the wake of the September 11, 2001, attacks in the United States.
Blunkett should end the detention without trial of foreign terrorist suspects "as a matter of urgency", the all-party Joint Committee on Human Rights said in a damning report published on Wednesday.
Under Britain`s anti-terrorism law foreign nationals who are suspected of being international terrorists can be interned indefinitely.
Home Office figures show that fewer than one in five of those arrested under the Terrorism Act 2000 were subsequently charged with offences under the legislation.
Of 562 people arrested under the Act between September 2001 and May this year, 97 have been charged under the legislation and 14 have been convicted.
A total of 280 people have been released without charge and with no further action being taken, while the remainder face charges unrelated to terrorism.