Extra drugs dogs used at RAF Brize Norton air base
Checks on returning soldiers have been stepped up at RAF Brize Norton after allegations that British troops have smuggled heroin out of Afghanistan.
For the past two weeks, extra sniffer dogs have been used at the Oxfordshire air base.
The Ministry of Defence (MoD) has stressed the claims are unsubstantiated but confirmed military police were investigating.
Brize Norton is the main air base for troops flying to and from Afghanistan.
Officials estimate 15,000 service personnel pass through the Oxfordshire air passenger terminal every month.
Reports 'taken seriously'
The inquiry is also focusing on service personnel at airports in Camp Bastion and Kandahar in Afghanistan.
An MoD spokesperson said: "We take any reports very seriously and have already tightened our existing procedures both in Afghanistan and in the UK."
The spokesperson also confirmed the investigation began after the MOD were tipped off that a British newspaper was planning to publish a story about the allegations.
Earlier this year four service personnel and four civilians were charged with plotting to smuggle more than a million cigarettes into the country on military aircraft through Brize Norton.