U.S. troops have guns at the ready amid spike in Afghan "insider attacks"

(CBS News) Amid the growing trend of what the U.S.-led coalition in Afghanistan now calls "insider attacks," U.S. troops have been instructed to keep their weapons loaded and ready at all times, even when they're on base.

On Friday, two U.S. soldiers were killed when a new recruit to the Afghan Local Police turned his gun on them moments after being handed a weapon during an inauguration ceremony- one of two such attacks that day; the other involved a member of the Afghan security forces shooting and wounding two foreign troops in the southern Kandahar province.

The frequency of these "insider attacks," until recently known as "green-on-blue" attacks, has risen dramatically this year as NATO remain on a path to hand over security operations to the Afghans by the end of 2014. The 31 attacks so far in 2012 account for nearly half of all such incidents recorded since 2007. In all, 39 ISAF (International Security Assistance Force) troops have been killed, including 25 Americans.

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The shooting carried out by the police recruit, who was killed in the attack, comes one day after a statement released by the head of the Afghan Taliban, Mullah Omar, claiming that militants had successfully infiltrated Afghan security forces to carry out such attacks.

The Taliban often claim responsibility for these attacks, but the U.S. Defense Department maintains they are generally not carried out by insurgents, but rather individual members of the Afghan security forces who may develop a grudge against their Western allies.

Watch above as Kitty Logan reports on the latest developments regarding "insider attacks" in Afghanistan.