SEOUL, South Korea - For the past decade, the world's most powerful nations have turned to sanctions in an attempt to punish North Korea for a series of rocket launches and nuclear tests. Their stated goal: to stop North Korea's march toward acquiring an arsenal of nuclear-armed long-range missiles.
The sanctions, however, have failed to slow Pyongyang down. It conducted a third nuclear test Tuesday despite warnings of more international punishment.
Once again countries are looking to the United Nations to tighten already harsh multilateral sanctions.
But the U.S. and its allies will also consider boosting their own national penalties against North Korean companies and individuals.
Here's a look at these countries' current non-U.N. sanctions and the reasons why many argue that for any real change to happen in North Korea, a reluctant China must also embrace tough, unilateral penalties against its ally.
China is seen as the only major power with any real influence on North Korea as it pursues nuclear weapons. It provides most of North Korea's fuel, a good deal of its food and accounts for an increasing share of its trade and investment.
But despite recurring nuclear and missile tests by Pyongyang, Beijing has been reluctant to take unilateral action against a neighbour it sees as a valuable buffer between U.S. troops stationed in South Korea and Japan.
"China can make a difference," said Andrei Lankov, a professor at Kookmin University in Seoul. "The question is whether it will make a difference."
Beijing's current options range from issuing harsh condemnation to supporting sterner U.N. sanctions, something it did after the North launched a rocket in December that the U.N. said was a cover for a banned missile test.
But many outsiders are pushing for more, including calls for China to restrict its food and fuel aid.
Beijing, for example, could turn "off the spigot of the Daqing pipeline that supplies (North Korea) with much of its oil, as Beijing did nearly a decade ago in March 2003," according to Elizabeth Economy, an Asia specialist at the Council on Foreign Relations.
But Kim Dong-gil, deputy director of the Center for Korean Peninsula Studies of Peking University, said that although China will likely sign on to whatever measures are agreed upon at the U.N., he strongly doubts China will take unilateral action against the North.
China's "unpleasant choice," Lankov said, is "between a nuclear, relatively stable North Korea, and a non-nuclear but unstable North Korea." For China, political collapse in North Korea "is a greater evil than North Korea's nuclear adventures."
Still, there is growing disgust among the government and the public in China with Pyongyang's behaviour.
The nuclear test, which took place less than 100 kilometres (62 miles) from the Chinese border, was widely criticized on China's popular Twitter-like Weibo microblogging service, with users calling it anti-social and urging the government to reconsider its assistance to the Pyongyang.
"Can China really allow this insane country to have nuclear weapons," wrote a user identified as Little Eagle King.
The U.S. does not maintain a comprehensive embargo against North Korea, as is sometimes presumed, and Americans are still free to travel there.
But legislation and executive orders, some dating back six decades, strictly regulate trade and aid, and assets are blocked for dozens of sanctioned North Korean companies, government agencies and individuals.
Washington is considered a sanctions trailblazer.
"Attention will now turn to Washington to see if the Obama administration lives up to its promise of significant repercussions if Pyongyang so blatantly and quickly disregards the latest U.N. resolution," said Bruce Klingner, a former U.S. intelligence official and now a North Korea analyst at the conservative Heritage Foundation think-tank in Washington.
Justification for U.S. restrictions includes Cold War-era legislation that regulates U.S. dealings with communist countries, worries about the spread of weapons of mass destruction and North Korea's poor record on human rights, religious freedom and human trafficking.
Trade between the countries is minimal. U.S. companies can export to North Korea, but have to apply for a license to do so.
For nearly all items, other than food and medicine, there is a presumption the request will be denied, according to a 2011 report by the Congressional Research Service. There are tight controls on access to computers and software. Arms transfers and sales are forbidden.
The Treasury Department must approve any imports from North Korea, and weighs all requests on proliferation concerns and on questions of who might profit. Transfers from the North Korean government itself are generally prohibited. Using a North Korea-flagged vessel for any transaction is prohibited.
The U.S. blocks North Korea from receiving support from international financial institutions like the World Bank and International Monetary Fund. Aid from the U.S. itself is also heavily restricted. North Korea is barred from government programs offering credit and investment guarantees.
The U.S. blocks assets and business transactions with individuals and entities on a sanctions list maintained by the Treasury Department's Office of Foreign Assets Control because of their suspected involvement with North Korea in weapons proliferation and other arms-related material, money laundering, counterfeiting, narcotics trafficking and trade in luxury goods.
Klingner called for Washington to set up more unilateral sanctions against not only North Korean entities but also "all those other banks, businesses and government agencies of other countries that have facilitated North Korea's behaviours. Washington needs to call upon other nations to match our efforts."
Seoul slapped independent sanctions on rival Pyongyang after the 2010 sinking of a South Korean warship that Seoul blames on Pyongyang. North Korea denies involvement in the sinking, which killed 46 South Koreans.
Those measures banned North Korean ships from entering South Korean waters, slashed cross-border trade, restricted South Koreans from travelling to North Korea, and prohibited additional investment in North Korea. Humanitarian aid was drastically cut, except for certain cases, including that for infants and other vulnerable people. Travel restrictions have been eased in some cases.
South Korea also bans luxury items from being shipped into North Korea. That includes liquor, cosmetics, leather goods, fur products, carpets, jewelry, electronics, vehicles, boats, optical equipment, watches, musical instruments and antiques.
Seoul says it is open to all possibilities but isn't currently mulling new unilateral sanctions and believes the 2010 penalties are putting pressure on North Korea.
Japan bans exchanges of people, goods, ships and flights between the two countries. In principle, no North Korean citizens are allowed to visit, while Japanese are asked to abstain from travelling to North Korea.
Tokyo also limits the amount of cash that can be carried to North Korea to 100,000 yen, while payments of 3 million yen or more must be reported to the government. Japan also bars North Koreans from receiving technical education and training related to sensitive nuclear technology.
A government official, who requested not to be identified because the information was not given through formal disclosure procedures, said Tokyo will follow the lead of other major nations in determining any further sanctions.
Associated Press writers Sam Kim and Youkyung Lee in Seoul, South Korea, Elaine Kurtenbach and Malcolm Foster in Tokyo, Matthew Pennington in Washington, and Christopher Bodeen in Beijing contributed to this report.