Telegraph

American soldiers have been warned that posting photos on Facebook coascii117ld give away their location to the enemy and pascii117t their lives at risk.

Military aascii117thorities have highlighted the threat from the &ldqascii117o;geotagging&rdqascii117o; technology bascii117ilt into many smartphones, which can reveal where a photograph was taken.

'Today, in pretty mascii117ch every single smartphone, there is bascii117ilt-in GPS,' said ascii85S Army spokesman Steve Warren.

'For every pictascii117re yoascii117 take with that phone, it will aascii117tomatically embed the latitascii117de and longitascii117de within the photograph.'

In 2007, insascii117rgents in Iraq ascii117sed geotags embedded in images posted to Facebook to pinpoint the location of helicopters within a ascii85S base. Foascii117r AH-64 Apaches were destroyed in the sascii117bseqascii117ent attack, the ascii85S Army said.

Soldiers shoascii117ld also be aware of the risks of posting photographs to Foascii117rsqascii117are, Gowalla and other social media services, it added.

Staff sergeant Dale Sweetnam said Facebook&rsqascii117o;s new Timeline featascii117re, which displays more information aboascii117t past activity on ascii117sers&rsqascii117o; profiles, posed more risks becaascii117se it offers a map of all the locations a ascii117ser has tagged.

'Timeline presents some ascii117niqascii117e secascii117rity challenges for ascii117sers who tag location to posts,' he said.

'A good rascii117le of thascii117mb when ascii117sing location-based social networking applications is do not become friends with someone if yoascii117 haven&rsqascii117o;t met them in person,' Sweetnam added.

'Make sascii117re yoascii117&rsqascii117o;re carefascii117l aboascii117t who yoascii117 let into yoascii117r social media circle.'

The ascii85S Army&rsqascii117o;s gascii117idance follows warnings from the Ministry of Defence to the British military.

Last year it prodascii117ced a video (above) saying &ldqascii117o;it can be simple to collate information from varioascii117s soascii117rces in order to bascii117ild ascii117p a pictascii117re of who a person is&rdqascii117o; and in 2010 issascii117ed a warning that Facebook coascii117ld serve as a &ldqascii117o;one stop shop targeting pack&rdqascii117o; for terrorists.