BERLIN — North Korea's closest neighbors responded to the news of leader Kim Jong Il's death by bracing for possible destabilization in the region, while across the globe, other nations expressed cautious optimism that the change of leadership could provide an opportunity to usher in reforms.

North Korea's past erratic behavior made it difficult to predict the course that its newly named leader, Kim's 20-something son Kim Jong Un, would choose during the transition. Japan and South Korea quickly held emergency meetings, while China, a key North Korean ally, pledged continued support.

Chinese Foreign Ministry spokesman Ma Zhaoxu said Beijing would continue to support its neighbor and make "active contributions to peace and stability on the Korean peninsula and in this region."

Kim's death was announced Monday by North Korean state television, two days after he died at age 69 of a heart attack.

During his 17 years in power, Kim's pursuit of nuclear weapons and his military's repeated threats to South Korea and the U.S. stoked fears of military conflict or that North Korea might provide weapons of mass destruction to terrorist movements.

South Korea put its military on "high alert" and President Lee Myung-bak convened a national security council meeting. The Korean peninsula remains technically in a state of war more than 50 years after the Cold War-era armed conflict there ended in a cease-fire.

Japanese Prime Minister Yoshihiko Noda held an emergency national security council with top Cabinet members soon after hearing the news. He expressed condolences and said Japan hoped Kim's death would not affect the region adversely.

"First of all we hope that this sudden development would not give adverse impact on the peace and stability of the Korean Peninsula," he said.

The White House said it was in constant contact with South Korea and Japan, but offered no substantive comment on the implications of Kim's death, saying only that President Barack Obama "reaffirmed the United States' strong commitment to the stability of the Korean peninsula and the security of our close ally, the Republic of Korea."

U.N. Secretary-General Ban Ki-moon is extended his sympathy to the people of North Korea, U.N. deputy spokesman Farhan Haq said. He added that Ban "reaffirms his commitment to peace and security on the Korean peninsula" and is closely following events.

China has long sought to convince North Korea of the need for economic reform, and Kim's death raises hopes that Pyongyang might now take heed of such advice, said Korea expert Lu Chao at China's Academy of Social Sciences in Liaoning province, which borders North Korea.

"There will definitely be change, good and positive change," Lu said. "North Korea will work more closely with the global community toward the peace and stability of the Korean Peninsula."

China is also expected to take a strong behind-the-scenes role to help retain its influence, which is seen as important no matter which direction North Korea takes, said U.S. Naval Academy China scholar Yu Maochun.

"If North Korea continues to be an international pariah, China will continue to benefit from its current leverage," Yu said. "If North Korea becomes less intransigent and slightly more open, then China will be greatly worried about the possible warming-up, or even reunification, between North and South Koreas."

The news jolted financial markets in Asia, raising the specter of more instability. But after Asian indexes closed lower, European stocks recovered their poise. Germany's DAX rose 0.8 percent to 5,747 and Paris' CAC 40 index rose 1 percent to 3,001. Britain's FTSE was flat at 5,388. Wall Street opened higher, with the Dow up 0.2 percent.

Moscow said it hoped for continued good relations with Pyongyang.

"We have friendly relations with North Korea," Russian Foreign Minister Sergey Lavrov said, according to the RIA Novosti news agency. "We hope that this loss that the Korean people have suffered will not have a negative impact on the development of our relations."

Australia's Foreign Minister Kevin Rudd said Kim's death brings the situation to "one of those critical junctures" and "an exceptionally difficult period of transition."

"It is critical that everybody exercises appropriate calm and restraint in what is a important development in terms of the overall stability of the region and the security of us all," Rudd said.

Britain's Foreign Secretary William Hague expressed his condolences, but added "this could be a turning point for North Korea."

"We hope that their new leadership will recognize that engagement with the international community offers the best prospect of improving the lives of ordinary North Korean people," Hague said in a statement, encouraging the country to resume international talks on its nuclear capabilities.

Germany's Foreign Ministry said it viewed the new leadership as an opportunity for change, spokesman Dirk Augustin told reporters.

"We have clear demands to North Korea: It must abandon its nuclear program; the catastrophic situation of the people must improve; and political and economical reforms must be implemented," Augustin said.

Venezuelan President Hugo Chavez expressed condolences and "his sincerest sorrow" at Kim's death, his government said in a statement.

Chavez has maintained friendly ties with North Korea. The Venezuelan government said it stands in solidarity with the North Korean people at "the loss of their leader, while having complete confidence in the ability of Koreans to guide their own future toward prosperity and peace."

With so many questions in the air at the moment, most countries are waiting to see what comes next.

"The death of a dictator is always a period of uncertainty for a dictatorship," said Swedish Foreign Minister Carl Bildt on Twitter. "And North Korea is the hardest dictatorship in our time."

Associated Press Writer David Rising and other writers around the world contributed to this report.