A North Korean propaganda media outlet criticized South Korea's deployment of stealth fighter jets, calling the move an unacceptable act of betrayal. 

The North's propaganda Web site "Uriminjokkiri" said on Sunday that the introduction of the fighter jets is a hostile act that escalates military tension on the Korean Peninsula, and an outright challenge to peace-building efforts.

It added that South Korea should ponder the catastrophic consequences of the jet's introduction, which runs counter to inter-Korean declarations and military agreement.

South Korea agreed to purchase 40 F-35A fighter jets from the U.S. defense firm Lockheed Martin, and received the first two late last month. The stealth fighter jets will be delivered in stages by 2021.