Fmr. U.S. envoy: Attack shakes U.S. confidence in Afghan security

(CNN) – A gunman believed to be an Afghan soldier opened fire at a training facility in Kabul and killed an American general – Maj. Gen. Harold Greene. The carnage marked the death of one of the highest-ranked U.S. military service members since 9/11, a Pentagon spokesman said.

A former U.S. envoy to Afghanistan said this attack undermines the United States' confidence in the ability of Afghans to take control of their own security in the next few months.

"From our side, that's part of the objective of the Taliban and their supporters in Pakistan, their enablers, and that is to lower the support for Afghanistan," said Peter Tomsen, former U.S. envoy and author of "The Wars of Afghanistan."

"I think the Afghans are determined now and they're very proud of what they've done since taking over all combat operations in all 34 provinces last year with our support," said Tomsen.

For more of our interview with former U.S. envoy Peter Tomsen, check out the video above.