Chinese media says North Korean leader Kim Jong-il has increased visits to military units after the confirmed US deployment of F-117 stealth fighters to South Korea.

A semi-official publication on Wednesday quoted Russia's RIA Novosti news agency as saying Kim visited bases three times in a week and stressed defense preparedness to soldiers.

Kim also called the deployment a grave threat to his country.

The units he reportedly visited were not disclosed, but Novosti believed they were stationed near the inter-Korean border.

Washington insists the F-117 deployment is part of its preparation for a long-planned drill. But some US dailies say the move is meant to increase pressure on Pyongyang, which has called the deployment "a risky prelude to war."