A major security operation in which a US airbase in Suffolk was sealed off started because a dog sat down, military chiefs have confirmed.

A major security operation in which a US airbase in Suffolk was sealed off started because a dog sat down, military chiefs have confirmed.

An Army bomb disposal team was sent to RAF Lakenheath after a suspicious package was reported by checkpoint staff at about 8.30am today.

The drama unfolded after one of the sniffer dogs used on the gates of the American airbase sat down - a signal that it might have found something suspicious.

A number of buildings around the main gate were evacuated amid fears that the truck trying to enter the base was carrying a bomb.

A 500-foot cordon was established around Gate 1 at the base and traffic was diverted off the usually busy A1065 to avoid the area.

And the suspect package was blown up in a controlled explosion carried out by an Army bomb disposal team based at Colchester in Essex.

It later emerged the package was not an explosive, inert in the words of MOD police, and the A1065 was reopened shortly before 1.30pm.

An MOD police spokesman said they could not reveal what the package was.

A spokeswoman for the base said: 'The checks had indicated that there may be a suspicious package on a vehicle, which had approached the gate.

'As a precaution, a 500foot cordon was put in place around Gate 1 and traffic on the A1065 was diverted to avoid the area.

'As a precautionary measure, base officials evacuated people from several surrounding facilities.

'They have sniffer dogs out and they are trained when they sniff something to sit down. A dog sat down and everything kicked off.'

Although the exact numbers of people moved from the affected area was unclear, the base spokeswoman said it was unlikely to have been a large number because only the visitor centre and a couple of other buildings would have been within the cordoned-off area.

For drivers trying to get down the A1065, the road blocks set up hundreds of metres from the cordon area triggered frustration and delays.

One motorist, who did not want to be named, said: 'We've not been told anything about what is going on and I'm trying to get home.'