But Pyongyang has feinted toward conciliation before and failed to follow through.
The North's gestures came after South Korea launched fighter jets, evacuated hundreds of residents near its tense land border with the North and sent residents of islands near disputed waters into underground bunkers in case Pyongyang followed through on its vow to attack over the drills.
"It appears that deterrence has been restored," said Daniel Pinkston, Seoul-based analyst with the International Crisis Group think tank. "The North Koreans only understand force or show of force."
North Korea has previously been accused of using a mix of aggression and conciliatory gestures to force international negotiations that usually net it much-needed aid. Real progress on efforts to rid the North of its nuclear weapons programs has been rare.
On Nov. 23, the North shelled Yeonpyeong Island, a tiny enclave of fishing communities and military bases about seven miles (11 kilometers) from North Korean shores in response to an earlier round of South Korean live-fire maneuvers. The North's artillery barrage killed two marines and two construction workers in its first attack targeting civilian areas since the 1950-53 Korean War. That clash sent tensions soaring between the two countries -- which are still technically at war.
They've remained in a tense standoff since then`, and an emergency meeting of U.N. diplomats in New York on Sunday failed to find any solution to the crisis.
But Monday brought some of the first positive signs in weeks, as a high-profile American governor announced what he said were two nuclear concessions from the North.
New Mexico Gov. Bill Richardson, a frequent unofficial envoy to North Korea and former U.S. ambassador to the U.N., said that during his visit the North agreed to let U.N. atomic inspectors visit its main nuclear complex to make sure it's not producing enriched uranium for a nuclear bomb, according to a statement from his office.
The North expelled U.N. inspectors last year, and last month showed a visiting American scientist a new, highly advanced uranium enrichment facility that could give it a second way to make atomic bombs, in addition to its plutonium program. Richardson also said that Pyongyang was willing to sell fresh fuel rods, potentially to South Korea.
"We had positive results," Richardson told Associated Press Television News at the Pyongyang airport Monday night. He had been set to brief reporters in Beijing, but his flight was canceled.
"This is the way countries are supposed to act," U.S. State Department spokesman P.J. Crowley said. "The South Korean exercise was defensive in nature. The North Koreans were notified in advance. There was no basis for a belligerent response."
Analyst Baek Seung-joo cautioned that the North's reported concessions are only a tactic aimed at easing international pressure. Baek, of the state-run Korea Institute for Defense Analyses in Seoul, said the comments would be significant if the North made them officially, rather than through Richardson.
The North was only sounding out U.S. and South Korean intentions by talking to Richardson, Baek said, and if the situation doesn't turn in the North's favor, it will back away.
Pyongyang is believed to be seeking one-on-one talks with Washington before returning to stalled nuclear disarmament negotiations hosted by China. The U.S., however, has indicated that a resumption of those talks, without meaningful movement on past nuclear commitments from the North, could be seen as tantamount to rewarding North Korea for behaving badly.
China has urged a resumption of the talks, and diplomats said Beijing successfully prevented Sunday's U.N. Security Council meeting from issuing a statement condemning the North's shelling -- as the U.S. and others had wanted.
On Monday, China's deputy U.N. ambassador Wang Min urged both sides "to exercise maximum restraint," avoid increasing tensions and solve differences through peaceful dialogue and engagement.
"China will continue to make every efforts towards this end," he said. "Calm rather than tensions, dialogue rather than confrontation, peace than warfare -- this is the strong aspiration and voice of the peoples from both sides of the peninsula and the international community."
Diplomats at the U.N. blamed China for refusing to condemn North Korea for two deadly attacks this year that helped send relations to their lowest point in decades.
Wang called the Security Council meeting "positive and of great importance" without any mention of its failure to agree on a statement. He noted that "members of the council, including China, the United States and Russia, have made efforts to the extent possible to avoid armed conflicts on the peninsula."
China is the North's most important ally and has come under pressure to leverage its influence to rein in the North in the wake of the attack.
Beijing, which provides crucial food and fuel aid to Pyongyang, is wary of pressuring the North in a way that could destabilize it, fearing in part a government collapse and a flood of refugees into northeastern China.
It was unclear if China persuaded North Korea not to react to Monday's drills.
Richardson appeared to suggest that his visit contributed to the North's backing down.
"During my meetings in Pyongyang, I repeatedly pressed North Korea not to retaliate. The result is that South Korea was able to flex its muscles, and North Korea reacted in a statesmanlike manner," Richardson said in a statement. "I hope this will signal a new chapter and a round of dialogue to lessen tension on the Korean peninsula."
North Korea called Monday's drills a "reckless military provocation" but said after they ended that it was holding its fire because Seoul had changed its firing zones.
The official Korean Central News Agency carried a military statement that suggested the North viewed Monday's drills differently from those that provoked it last month because South Korean shells landed farther south of the North's shores.
The North claims the waters around Yeonpyeong as its territory, and during last month's artillery exchange, the North accused the South of firing artillery into its waters; the South said it fired shells southward, not toward the North.
South Korea's Joint Chiefs of Staff said its artillery Monday was fired in the same direction -- toward waters southwest of the island, not toward the North -- as last month's maneuvers.
"North Korea appeared to have issued this statement because it was afraid" of a full-blown war with South Korea, a Joint Chiefs of Staff officer said on condition of anonymity citing department rules.
In Washington, the Pentagon called the drills routine. There was nothing "provocative, unusual or threatening about them," said Defense Department spokesman Lt. Col. Mark Ballesteros.
South Korean President Lee Myung-bak ordered preparations to cope with any possible attack by North Korea, even after the drills ended.
Several bloody naval skirmishes have occurred in recent years along the Koreas' disputed western sea border, which the North does not recognize.