Tensions rose Monday on the Korean peninsula, with Pyongyang releasing video of a major military exercise and Seoul accusing the North of using a planned satellite launch as a pretext for testing a nuclear weapon delivery system.

The North Korean video shows leader Kim Jong Un meeting soldiers and watching what is described as a joint strike drill of the North's army, navy and air force. The video shows a warship being blown up at sea, soldiers firing missiles and an airplane exploding in mid-air.

The release comes as South Korean officials denounced Pyongyang's announcement Friday that it will launch a rocket in mid-April to put a satellite into orbit for peaceful purposes.

After a morning meeting of foreign and security ministers, presided over by South Korean President Lee Myung-bak, a presidential spokesman described the planned launch as a “grave provocation.”

“Our government defines North Korea's so-called working satellite launch plan as a grave provocation to develop a long-distance delivery means for nuclear weapons by using ballistic missile technology. South Korea will work closely together with the United States, Japan, China, Russia and the European Union during next week's Nuclear Security Summit in Seoul to deal with the issue.”

He said the real purpose of the launch is to develop of a long-range missile capable of carrying a nuclear payload.

The spokesman also said South Korea would work with the international community and discuss the matter with the leaders of related countries, including the United States, Japan, China, Russia and the European Union during next week's Nuclear Security Summit in Seoul.

The U.S., Russia, South Korea and Japan have all condemned the planned launch, saying it violates a U.N. ban on all North Korean launches using ballistic missile technology.

U.N. Secretary-General Ban Ki-moon said on Friday that such a launch could affect plans to deliver food aid to the impoverished North.