Speaking from his headquarters in Kabul, U.S. Army Gen. Dan K. McNeill said opium poppy cultivation remains a major threat to Afghanistan, the U.S. Defense Department said in a news release.

"In some portions of the country right now, mostly in the south, the cultivation of poppy is a far greater threat to the Afghan government -- to the security and stability here -- than the insurgency," McNeill said.

The Afghan government must head up the elimination of opium poppy cultivation as the country's economic base, McNeill said, estimating that the Taliban and al-Qaida receive between 20 percent and 40 percent of their money from the drug trade.

The United Nations estimates the terrorist groups receive closer to 60 percent from drugs.

"We are in there fighting insurgents who are as much narco-dealers as they are insurgents," McNeill said. "In some cases, we are fired upon by people doing narco-business."