An unusually blunt Secretary of State John Kerry said Thursday that China's diplomatic strategy to defuse the North Korean nuclear strategy simply hasn't worked.

The Chinese government on Wednesday successfully conducted a test civil flight to an airport on Yongshu Jiao of China's Nansha Islands to ensure the safety of the airport for large airliners and provide options for new alternate airfields and more flexible and cheaper transoceanic flight routes.

North Korea's main ally China says it "firmly opposes" Pyongyang's purported hydrogen bomb test and is monitoring the environment on its border with the North near the test site.

North Korea said Wednesday that it successfully staged its first test of a more powerful form of a nuclear weapon, expanding the U.S.’s foreign-policy challenges and highlighting the limits of China’s ability to rein in its volatile ally.

North Korea is "likely" to have conducted a nuclear test that caused an earthquake near a known testing site in the isolated country, South Korea's meteorological agency said on Wednesday.

China moved to support its sinking stock market as state-controlled funds bought equities and the securities regulator signaled a selling ban on major investors will remain beyond this week’s expiration date, according to people familiar with the matter.

China and Pakistan completed a joint two-day naval drill on Friday. It was the first time the two militaries conducted the exercise in the East China Sea.

Chinese stock markets tumbled 7 percent in their opening session of 2016 on Monday as weak factory activity surveys and falls in the yuan added to concerns about the struggling economy, forcing exchanges to suspend trade for the first time.

The Philippines says that like Vietnam, it opposes a recent Chinese flight test in a newly completed runway on one of seven islands Beijing constructed in the disputed South China Sea.

China's factory activity contracted for the 10th straight month in December, and at a sharper pace than in November, a private survey showed, dampening hopes that the world's second-largest economy will enter 2016 on steadier footing.