North Korea ? North Korea has revalued its currency for the first time in a half century, reportedly triggering chaos in the impoverished nation by moving to assert state control over a growing market economy.

The development came at the end of a year of turmoil as leader Kim Jong Il apparently recovered from a stroke. The communist country also stoked tensions by launching a long-range rocket and conducting its second nuclear test, drawing U.N. condemnation and beefed-up sanctions.

North Korea revalued its currency — known as the won — at an exchange rate between old and new notes of 100 to 1, China’s Xinhua news agency said in a dispatch from Pyongyang. It cited a verbal notice Tuesday from North Korea’s Foreign Ministry to embassies in the capital.

The surprise move reportedly sent shockwaves through North Korea, with reports of shops being closed and citizens angry and panicked.

The exchange of old notes started Monday and will continue until Sunday, Xinhua reported. It said no reason was provided for the sudden change.