The drill comes a day after one B-1B supersonic bomber staged a simulated bombing exercise with two F-22 Raptors and four F-35A and F-35B Lightning II stealth fighter jets on the east coast.
China, North Korea's neighbour and lone major ally, has again urged calm and says war is not the answer as Pyongyang said military drills involving the US and South Korean forces made war "an established fact".
The bombers were dispatched from Andersen Air Force Base in Guam and flew over the Korean peninsula, reportedly staging simulated bombing drills while flying in formation with around 20 aircraft participating in the annual "Vigilant Ace" air combat drill.
The drills come a week after North Korea said it had tested its most advanced intercontinental ballistic missile capable of reaching the United States. "It is a trite method employed by aggressors to mount a sudden preemptive attack while pretending to conduct war drills", the article said.
It is reported by South Korean joint chiefs of staff.
"Series of violent war remarks coming from the US high-level politicians amid such circumstances have made an outbreak of war on the Korean peninsula an established fact", the spokesperson said.
Russian Federation and China both responded by pushing the US and North Korea away from war.
"The great success in the test-fire of ICBM Hwasong-15 is a priceless victory won by the great and heroic people of the DPRK who have upheld the WPK's line on the simultaneous development of the two fronts with loyalty", North Korea said in a statement, "without the slightest vacillation, despite the vicious challenges by the US imperialists and their followers and manifold difficulties".
"We hope all relevant parties can maintain calm and restraint and take steps to alleviate tensions and not provoke each other", Chinese Foreign Ministry spokesman Geng Shuang said.
North Korea said that further escalation through joint drills "will only invite more bad retaliation and precipitate their self-destruction".
Moscow also believes it is Washington's saber-rattling and regular military drills in the region that are "provoking Pyongyang into taking some rash action" after months of restraint, Russian Foreign Minister Sergey Lavrov said following the country's latest ballistic missile test. Threats from various U.S. officials are serving the same goal, Lavrov added.
While B-1Bs are no longer equipped to carry nuclear weapons of their own, they would be key to any strike targeting major North Korean facilities, he said.
"We know that North Korea wants above all to talk to the United States about guarantees for its security". Feltman met North Korean foreign minister Ri Yong Ho on Thursday, North Korea's official KCNA news agency said.