North Korea has recently moved troops and artillery weapons near the capital city of Pyongyang, in a move believed to be preparation for a large-scale fire power drill, a military source said Monday.

The North Korean military has been conducting the winter exercise since early December, firing off a spate of rockets and missiles, and conducting infiltration drills near the border. 

Amid the ongoing training, North Korean forces and artillery pieces have moved to Mirim Airport near Pyongyang, where military parades are held during significant national anniversaries. 

"The North Korean military is believed to be preparing a large-scale fire drill involving multiple rocket launchers and self-propelled howitzers," the source said, asking for anonymity. 

Pyongyang has annually staged a large-scale fire drill during the final stage of its winter drills, which was observed by North Korean leader Kim Jong-un. 

In March 2013, Kim visited Wonsan on the eastern coast where the North Korean military carried out a firearm drill involving various artillery weapons. 

The latest move comes at a time of heightened tensions on the Korean Peninsula as the North has angrily responded to the annual joint military drills between South Korea and the United States. 

The South Korean military has been closely monitoring the North Korean military, carrying out amphibious landing drills with the U.S. forces over the weekend as part of the combat field exercise Foal Eagle, which runs through April 18. 

"There is a possibility that North Korea may launch landing drills in response to the South Korea-U.S. Foal Eagle exercise following the firearm exercise," another military official said. 

In the latest of a series of missile launches in recent weeks, Pyongyang fired off two mid-range missiles capable of hitting Japan, sparking condemnation from the U.N. Security Council. 

In response, the communist state on Sunday vowed not to rule out a "new form" of atomic test to bolster its nuclear deterrence. (Yonhap)