The US and South Korean militaries are now participating in an air-power exercise on the Korean Peninsula involving a record number of stealth jets and an increased pace of simulated bomb runs.
The US carried out another simulated bomb run with a supersonic B-1B bomber on Wednesday, but this time it included the US's top-of-the-line air superiority fighter, the F-22, according to Yonhap.
A total of 12,000 USA service members are taking part in the annual Vigilant Ace drills alongside South Korean troops.
The most recent drills included USA warplanes, including nuclear-capable bombers, running practice drills near the North Korean frontier.
The Guam-based Lancer bombers trained with more than 20 fighter jets as part of the Vigilant Ace joint exercise with South Korea, which began on December 4 and will continue until Friday.
The Chinese Ministry of Foreign Affairs on Wednesday expressed concerns over the continued deployment of US strategic assets.
"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 in a statement.
North Korean state media - which describes the B-1B Lancer as a nuclear strategic bomber - denounced the exercise over the weekend.
But with the USA using its best planes to message North Korea, and Pyongyang demonstrating missiles that experts assess can hit anywhere in the U.S., it's unclear just how much higher tensions on the Korean Peninsula could escalate.
Wednesday also saw a spokesperson for the DPRK Ministry of Foreign Affairs say Pyongyang would not avoid a war with Washington, criticizing recent "reckless remarks" by high-level American politicians.
A nuclear war with the United States is an established fact and the only question is when it will break out, a North Korean spokesman said last night.
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.
North Korea said that further escalation through joint drills "will only invite more awful retaliation and precipitate their self-destruction".
The weekend saw both White House national security adviser H.R. McMaster and U.S. Senator Lindsey Graham of SC say chances of war with Pyongyang were growing. The two countries kicked off their largest ever joint air exercise on Monday.
The unnamed Foreign Ministry spokesman said: 'The large-scale nuclear war exercises conducted by the United States in succession are creating touch-and-go situation on the Korean peninsula and series of violent war remarks coming from the USA high-level politicians amid such circumstances have made an outbreak of war on the Korean peninsula an established fact.