The U.S. military staged bombing drills with South Korea over the Korean peninsula and Russia and China began naval exercises ahead of a U.N. General Assembly meeting on Tuesday where North Korea's nuclear threat is likely to loom large.
The drills are the second part of China-Russian naval exercises this year, the first part of which was staged in the Baltic in July. Xinhua did not directly link the drills to current tension over North Korea.
China and Russia have repeatedly called for a peaceful solution and talks to resolve the issue.
On Sunday, however, Ambassador to the United Nations Nikki Haley said the U.N. Security Council had run out of options on containing North Korea's nuclear program and the United States might have to turn the matter over to the Pentagon.
President Donald Trump has vowed that North Korea will never be able to threaten the United States with a nuclear-tipped ballistic missile.
Asked about Trump's warning last month that the North Korean threat to the United States would be met with "fire and fury," Haley said: "It was not an empty threat."
Washington has also asked China to do more to rein in its neighbor and ally, while Beijing has urged the United States to refrain from making threats against the North.
The international community must remain united and enforce sanctions against North Korea after its repeated launch of ballistic missiles, Japanese Prime Minister Shinto Abe said in an editorial in the New York Times on Sunday.
Such tests were in violation of Security Council resolutions and showed that North Korea could now target the United States or Europe, he wrote.
Abe also said diplomacy and dialogue would not work with North Korea and concerted pressure by the entire international community was essential to tackle the threats posed by the north and its leader, Kim Jong Un.
Pyongyang has launched dozens of missiles as it accelerates a weapons program designed to provide the ability to target the United States with a powerful, nuclear-tipped missile.
It says such programs are needed as a deterrent against invasion by the United States, which has 28,500 troops stationed in South Korea. On Saturday, it said it aimed to reach an "equilibrium" of military force with the United States.
The United States and South Korea are technically still at war with North Korea because the 1950-53 Korean conflict ended with a truce and not a peace treaty.