A U.S. think tank is estimating that South Korea and the United States would need up to 460-thousand troops to stabilize the Korean Peninsula, should North Korea collapse. It would be three times more than the total number of U.S. troops deployed to Iraq.

The Council on Foreign Relations made the assessment in a report titled "Preparing for Sudden Change in North Korea." The report said the time has come for concerned parties to draw up preparations for sudden change in the North in the wake of reports that the communist state’s leader Kim Jong-il’s health is failing.

The report noted that securing North Korea's estimated six to eight nuclear weapons, four-thousand tons of chemical weapons, and any biological weapons, as well as its ballistic missile program, would be high priorities.

The report also stressed the need for the U.S. to seek "a quiet dialogue" with China "to reduce the risk of misunderstanding and friction in a crisis involving North Korea," saying Chinese interest in North Korea has increased due to the six-party talks.

According to the report, a prolonged contest regarding succession or an extended power vacuum after Kim’s demise would trigger various problems, including a possible armed conflict in either the demilitarized zone or Yellow Sea or even a massive North Korean exodus.