Flags of China and North Korea are seen outside the closed Ryugyong Korean Restaurant in Ningbo, Zhejiang province, China, in this April 12, 2016 file photo. Reuters

North Korean state media took a rare stab Thursday at the country's usual ally, China, after Beijing decided to halt coal imports over Pyongyang's nuclear program.

The government-run Korean Central News Agency ran a commentary entitled "Neighboring Country's Mean Behavior" that accused an unnamed nation "styling itself a big power" of "dancing to the tune of the U.S." by economically punishing the reclusive, authoritarian state over its recent missile tests and nuclear weapons program. China responded Saturday to North Korea's latest allegedly nuclear-capable ballistic missile launch earlier this month by restricting coal imports for the entirety of 2017.

China has been North Korea's largest trade partner and biggest diplomatic ally, but it has expressed opposition to Pyongyang's nuclear weapons program, which has increased dramatically since Kim Jong Un succeeded his father in 2011. North Korea has conducted five successful nuclear weapons tests and has claimed to possess the technology to fit these nuclear warheads on the missiles it possesses — a claim disputed by some experts.

Security analysts have estimated that North Korea has an array of missiles with varying ranges, some of which may be able to reach the U.S. Last month, Kim said the nation was close to developing intercontinental nuclear missiles.

China has applied economic pressure to North Korea in the past. Last year, analysts noticed a significant decrease in trade activity along China and North Korea's 880-mile border that may have been linked to its neighbor's nuclear tests. China also agreed to sign on to U.N. Security Council-drafted sanctions, which North Korea has described as illegitimate and a U.S.-orchestrated conspiracy.
The complex relationship between China and North Korea came into the spotlight last week when Kim Jong Un's half-brother, Kim Jong Nam, was assassinated Feb. 13 in a Malaysian airport. Kim Jong Nam had fallen out of favor with the North Korean government after voicing public criticism of its policies. As a precaution, he and his family enjoyed protection from China.
While North Korea has officially blamed Kim Jong Nam's death on its rival South Korea, his death may have a tangible effect on relations between Pyongyang and Beijing.