In a New York Times article, the Japanese Prime Minister notes that the worldwide community must remain united and apply the sanctions against North Korea after its multiple missile tests.
A week ago, the 15-member U.N. Security Council unanimously adopted its ninth sanctions resolution since 2006 over North Korea's nuclear and ballistic missile programmes.
The United States military has carried out several flights over the Korean Peninsula in joint bombing drills with the South amid escalating tensions between Washington and Pyongyang.
Four ROK Air Force F-15s take part with two US Air Force B1-B strategic bombers and four F-35 fighter jets in a joint exercise on September 18.
The US said it conducted the new military exercise with the South in response to the North's recent missile and nuclear tests, said the source.
The flurry of military drills came after Pyongyang fired another mid-range ballistic missile over Japan on Friday and the reclusive North conducted its sixth and most powerful nuclear test on September 3 in defiance of United Nations sanctions and other global pressure.
It said Beijing "will never accept the "responsibility" imposed by the U.S".
The US flew four F-35B stealth fighter jets and two B-1B bombers over the Korean peninsula on Monday in a show of force after North Korea's latest nuclear and missile tests, South Korea's defence ministry said.
Its request, however, was rejected during talks with Joseph Yun, special representative for North Korea policy, and Eliot Kang, acting assistant secretary of the Bureau of International Security and Nonproliferation. He previously said the idea should be "deeply considered" by the allies, inflaming already-heated debate on the issue.
South Korea and the United States are technically still at war with North Korea after the 1950-53Korean conflict ended with a truce, not a peace treaty.
"The so-called "China's responsibility theory" is essentially moral kidnapping", the People's Daily said in a commentary.
China and Russia started the second stage of their "Joint Sea-2017" military exercises on Monday with the arrival of a Chinese naval fleet in the Russian port city of Vladivostok.
President Donald Trump threatened to "totally destroy North Korea" in a speech to the United Nations On Tuesday.