U.N.: Colombian security forces executing innocent civilians

BOGOTA, Colombia (CNN) - Colombia's U.S.-backed security forces are engaging in "systematic and widespread" extrajudicial executions of innocent civilians as part of their counterinsurgency campaign, a top United Nations diplomat said Saturday.

Speaking in Bogota after a week-long fact-finding tour, Navi Pillay, the U.N. High Commissioner for Human Rights, said the scale of the killings could constitute a "crime against humanity" under international humanitarian law, adding that international courts could intervene if the Colombian government was "unwilling or unable" to handle the investigations itself.

"An offense becomes a crime against humanity if it is widespread and systematic against the civilian population," Pillay said at a news conference. "We are observing and keeping a record of the number of extrajudicial killings (in Colombia) and it does appear to be systematic and widespread in my view."