Three arrests have been made on the third day of Britain's huge security clampdown at airports around the country. Although authorities say those arrested Thursday are not believed to be linked to any plot to bring down a passenger plane, security remains tight at British airports.
One man, a 37-year-old Venezuelan was taken into custody at Gatwick Airport when a random customs check revealed he was carrying a live hand grenade in his luggage. He had just come off a British Airways flight from Colombia.
Meanwhile at Heathrow Airport, where the largest anti-terrorist police and army presence can be seen, two men were arrested near a perimeter fence. Police say they are being held as a precautionary measure.
Home Secretary David Blunkett says no one should jump to conclusions about Thursday's arrests but earlier in parliament he underlined that the threat to Britain, and aviation in particular, was very serious.
"We face a real and serious threat. We know that al-Qaida will try to inflict loss of human life and damage upon the United Kingdom," he said.
Mr. Blunkett added that the three arrests show that the security services are doing their job and he urged all people here to remain vigilant.
Although passengers at Heathrow Airport experienced just a few problems, many Gatwick flights were delayed and some were cancelled. The north terminal there was closed for a number of hours.
Without releasing details, authorities here say the heavy security deployment around Britain's airports was ordered after the analysis of specific intelligence information.