Seoul: North Korea warned on Friday that its military would not remain a "passive onlooker" if South Korea and the United States continued joint military drills, state media reported.
The threat came from Ri Yong-Ho, a vice marshal of the North`s armed forces, at a meeting attended by top government, military and party officials in Pyongyang.
In a speech published by state media, Ri said North Korean troops and people would not remain "passive" onlookers to what he called "provocative and aggressive nuclear war exercises" being staged by US and South Korean troops.
"The Army and people of (North Korea) will never remain a passive onlooker to them but resolutely frustrate them with the might of Songun (Army-first) which has been built up in every way," he said.
This year, South Korea has been staging a series of drills alone or together with US troops to test its battle readiness.
US and South Korean troops completed computerised joint war games on March 10, but joint field training will continue throughout April.
"National defence is the most important affair in building a thriving nation," Ri said.
South Korean Defence Minister Kim Kwan-Jin said this week the North may attempt surprise attacks across the sea border after practising marine infiltration drills.
He warned of the possibility of "various types of surprise local provocations".
The disputed Yellow Sea border was the scene of deadly naval clashes in 1999, 2002 and November 2009.
The South also says a North Korean submarine fired a torpedo to sink one of its warships in March 2010, with the loss of 46 lives.
Pyongyang denies that attack. But last November it shelled a border island, leaving four South Koreans including two civilians dead and briefly sparking fears of war.