Pyongyang conducted intercontinental ballistic missiles tests on Friday to prove its ability to strike America's mainland, drawing a sharp warning from US President Donald Trump.
The US flew two supersonic B-1B bombers over the Korean peninsula in a show of force on Sunday after Pyongyang's recent tests of intercontinental ballistic missiles (ICBM), the US and South Korean air forces said.
The manoeuvre came after the Democratic People's Republic of Korea (DPRK) celebrated the country's second intercontinental ballistic missile test in a month as Pyongyang said it conducted another successful test on Friday, proving its ability to strike America's mainland.
The B-1B flight was in direct response to the missile test and the previous July 3 launch of the "Hwasong-14" rocket, the US statement said.
The South Korean air force said the flight was conducted early on Sunday.
The bombers took off from a US air base in Guam, and were joined by Japanese and South Korean fighter jets during the exercise, according to the statement.
"North Korea remains the most urgent threat to regional stability," Pacific Air Forces commander General Terrence J O'Shaughnessy said in the statement.
"If called upon, we are ready to respond with rapid, lethal, and overwhelming force at a time and place of our choosing".
TRT World's Christine Pirovolakis reports on the tensions in the Korean peninsula.
Also on Sunday, the US Missile Defense Agency announced the US had successfully shot down a medium-range missile in the latest test of its THAAD missile defence program.
The test was planned well before the rising tensions with North Korea and involved a medium-range missile, not the long-range types being tested by the North Koreans.
China, the North's main ally, said it opposed North Korea's missile launches, which, it said, violate UN Security Council resolutions designed to curb Pyongyang's banned nuclear and missile programmes.
"At the same time, China hopes all parties act with caution, to prevent tensions from continuing to escalate," China's foreign ministry said in a statement on Saturday.
But US President Donald Trump said he was "very disappointed in China".
I am very disappointed in China. Our foolish past leaders have allowed them to make hundreds of billions of dollars a year in trade, yet...— Donald J. Trump (@realDonaldTrump) July 29, 2017
...they do NOTHING for us with North Korea, just talk. We will no longer allow this to continue. China could easily solve this problem!— Donald J. Trump (@realDonaldTrump) July 29, 2017
The Hwasong-14, named after the Korean word for Mars, reached an altitude of 3,724.9 kilometres (2,314.6 miles) and flew 998 km (620 m) for 47 minutes and 12 seconds before landing in the waters off the Korean peninsula's east coast, North Korean news agency KCNA said.
North Korean leader Kim Jong-un personally supervised the midnight test launch of the missile on Friday night.
He said it was a "stern warning" for the US that it would not be safe from destruction if it tries to attack, the North's official KCNA news agency said.
Western experts said calculations based on flight data and estimates from the US, Japanese and South Korean militaries showed the missile could have been capable of going as far inside the US as Denver and Chicago.
North Korea said on Sunday it had been forced to develop long-range missiles and nuclear weapons because of hostile intent by "American imperialist beasts" looking for another chance to invade the country.
"In case the US fails to come to its own senses and continues to resort to military adventure and 'tough sanctions', the DPRK will respond with its resolute act of justice as already declared," its foreign ministry said in a statement.