(CBS) -- Afghan border police detected a significant amount of bleach in fruit and coffee stored at their main border checkpoint between Afghanistan and Pakistan, a likely attempt to poison the Afghan security forces, according to a police source.
A border police source tells CBS News Kabul bureau chief Fazul Rahim the contaminated items were detected at the Torkham border crossing post before the food made it onto any tables.
He said the level of contamination was sufficient to draw attention and given the amount, must have been done intentionally.
There have been previous incidents of intentional food poisoning aimed at Afghanistan's civil defense forces, says Rahim, including a case in Kabul last year which involved some people being sickened.
Militants from the Taliban and other extremist groups have long targeted Afghanistan's security services and government officials for their alliance with U.S. and NATO forces, with both conventional bomb and gun attacks by any other means available.
There was no immediate claim of responsibility for the contamination at the Torkham border post - on the Afghan side of the largest crossing point between Afghanistan and Pakistan.
The incident comes amid a series of attacks targeting U.S. troops and interests in Afghanistan following the burning of Korans at a massive U.S. military base in the country.
CBS News correspondent Mandy Clark reports four American troops were wounded and at least nine Afghans killed in a suicide bomb attack Monday at the airport in Jalalabad, which doubles as a U.S. military base.