South Korea has held major military exercise less than 30 miles from the North Korean border, despite fears that such a major show of force could provoke fresh violence from the North.
The live fire drills — described as the biggest in the country's history — come a month after North Korea's shelling of Yeonpyeong Island and the deadly sinking in March of a South Korean warship that Seoul blames on Pyongyang.
Pyongyang has called the drills — involving about 800 troops as well as tanks, F-15 fighter-jets, multiple long-range rockets and Cobra helicopter gun ships — and smaller drills held earlier in the week as "provocative."
And New Mexico Gov. Bill Richardson, just back from a peacekeeping trip to the Korean peninsula, warned violence between North and South Korea could flare anew.
In an interview with The Associated Press, he said the large mobilization of weaponry and personnel was yet another test for the North, which had shown much restraint.
"The situation is still a tinderbox. There's still enormous tension, enormous mistrust and I believe diplomacy is what is needed to get us out of this tinderbox," said Richardson, who visits North Korea semi-regularly as an unofficial U.S. envoy.
Pyongyang this week also indicated it would allow U.N. inspection of its nuclear programs and be open to creating a hotline between the two countries to avoid potential crises.
"The conversations I had with them indicate to me that perhaps they're ready to turn a page, that they realize they went too far," Richardson said, referring to the ship sinking earlier this year and the country's nuclear activities.
"This isolation that they've imposed upon themselves, this bunker mentality is not working," he said. "Their people need food, their people need jobs, they need to get out of sanctions and I believe they realize this and it could be they're changing. But let there be verification because their credibility is suspect."