.K. Manhunt Under Way After 5 Held for Terror Attack

July 2 (Bloomberg) -- A manhunt was under way for further terrorist suspects after police arrested five people and searched houses following an attack on Glasgow International Airport and two attempted car bombings in London.

Prime Minister Gordon Brown's new government stepped up security in the U.K. Controls were tightened at airports, cars were checked and more police were patrolling crowded public areas. The Home Office raised its terrorist threat assessment to ``critical,'' the highest level, meaning an attack is expected imminently.

Two men were arrested at Glasgow airport June 30 after their Jeep Cherokee crashed into the terminal entrance and caught fire. Police arrested two more people, a 26-year-old man and 27-year- old woman, on the M6 highway in northwest England the same evening and a fifth, a 26-year-old man, in Liverpool yesterday.

The identity of the arrested suspects isn't ``certain,'' Home Secretary Jacqui Smith said when asked on Sky News whether the attackers were foreign or British. She said the ``public needs to be vigilant about potential threats'' of more incidents and added that Britain shouldn't be intimidated by the attacks.

An al-Qaeda-linked cell of eight people was behind the attempted bombings, with three remaining suspects still being sought, the Guardian newspaper reported today, citing unidentified counterterrorism officers. Two of those arrested are medical doctors, the British Broadcasting Corp. reported late yesterday.

`Long-Term Threat'

``It is clear that we are dealing in general terms with people who are associated with al-Qaeda in a number of incidents that have happened across the world,'' Brown said in an interview yesterday. ``We're dealing with a long-term threat. It's not going to go away in the next few weeks or months.''

There was little market reaction in London June 29 to the discovery of the first car bomb. Police announced the second London device, and the attack on Glasgow airport, after markets closed for the weekend.

U.K. government bonds, or gilts, gained today, pushing 10- year yields to near a three-week low. Analysts expect the pound to hold above $2 before the July 5 interest-rate decision by the Bank of England. It last traded at 2.0075, from 2.0088 at the close Friday. The benchmark FTSE 100 Index fell 29.20 to 6578.70 at 10:05 a.m.

Bush Support

U.S. President George W. Bush yesterday praised the Brown government's handling of the terrorist threats in London and Glasgow, calling it a ``very strong response.''

The British Cabinet's emergency committee, Cobra, named for Cabinet Office Briefing Room A, met yesterday for the fourth time in two days, a Downing Street spokeswoman said.

The Glasgow attack came as police were conducting one of their biggest manhunts after dismantling two car bombs made from gas canisters, gasoline and nails left in the heart of London's West End shopping and theater district three days ago.

``The links between the three attacks are becoming ever clearer,'' Peter Clarke, the U.K.'s chief anti-terrorism officer, said at a televised news conference yesterday. ``The investigation is extremely fast-moving. New information is coming to light hour by hour.''

Police said they were searching a number of houses in the Renfrewshire area, near Glasgow, as well as two addresses in Liverpool and a house in Staffordshire, north of Birmingham. Glasgow airport, which was closed to all flights June 30, resumed operations yesterday.

Aircraft Plot

The incidents prompted the biggest terrorism alert in the U.K. since authorities foiled an Islamist plot in August 2006 to blow up aircraft flying from Heathrow airport to the U.S. Terrorists killed 52 people in London on July 7, 2005, in suicide bombings on the subway and a bus.

``The real question is, is it part of a plan that is being directed by someone?'' said David Bentley, an analyst in terrorism law at London-based policy research group Chatham House. ``London today, Glasgow tomorrow, then maybe Birmingham or Manchester?''

In London, police were examining hours of images from security cameras to try to establish the cars' routes into the center of the city. They discovered the first bomb in a Mercedes parked outside a packed nightclub in Haymarket, close to Piccadilly Circus, at 1:30 a.m. on June 29.

The second device, in another Mercedes parked between Haymarket and Trafalgar Square, was found hours after the car was towed to a garage on Park Lane for being parked illegally.

The Jeep Cherokee crashed into a front entrance of Glasgow airport's main passenger terminal at 3:15 p.m. on June 30, catching fire on impact.

Suspect Burned

One of the two men from the Jeep was in police custody and the other was taken to the Royal Alexandra Hospital in Paisley and was in critical condition because of burns. Police carried out a controlled explosion of a suspect vehicle that was parked outside the hospital, Sky News reported late yesterday.

One other person who had been at the Glasgow terminal received hospital treatment for an injured leg, police said. Some passengers were stranded on planes after the attack because police didn't want to evacuate them through the terminal.

Glasgow, with a population of more than 1 million in the metropolitan area, is Scotland's largest city. The airport, operated by BAA Ltd., is 8 miles (13 kilometers) west of the city center and is the busiest of Scotland's three main airports.

Heathrow

London's Heathrow airport, Europe's busiest, shut traffic lanes closest to terminal buildings and urged travelers to arrive on public transportation. Terminal 3 was closed briefly late yesterday when an unattended bag was found, police said.

Dropping off and picking up in front of BAA airports is ``severely restricted,'' the company said in an e-mailed statement. BAA, owned by Grupo Ferrovial SA of Spain, operates Heathrow, Gatwick and five other U.K. airports.

Commuters returning to work in London today will notice increased security at rail stations and on the street, police said.

Vehicles approaching mainline rail stations, and their passengers, will be subject to random searches for the foreseeable future, a British Transport Police spokesman said.

At the Wimbledon tennis championships in southwest London, concrete blocks are being use to protect entry and exit points and the organizers urged visitors to use public transportation rather than private cars.

``We urge everyone coming to the event to allow more time for their journey,'' said Ian Ritchie, chief executive of the All England Club said on the club's Web site. ``Safety and security is of paramount importance to us.''