The United States and South Korea launched their biggest combined air force exercise yesterday with tensions high on the Korean peninsula a week after North Korea test-fired its most powerful missile, an ICBM that may be able to target the eastern seaboard of the US.

The five-day war games, involving hundreds of aircraft including two dozen stealth jets, is called Vigilant Ace and is meant to improve the allies' wartime capabilities, South Korea's Defence Ministry said.

The US Seventh Air Force sent major strategic military assets that include six F-22 and 18 F-35 stealth fighter jets for the annual training exercise in the Korean Peninsula. About 12,000 US military personnel are participating. Some local media report that B-1B bombers will also join aerial drills, but officials could not confirm the reports.

North Korea's state media said the joint drill pushes the Korean Peninsula "to the brink of nuclear war". North Korean sees US-South Korean drills, which are held regularly, as preparation for invasion.

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Still, tensions are at a particularly dangerous point as North Korea edges toward its goal of a viable arsenal of nuclear-tipped long-range missiles, and President Donald Trump uses aggressive rhetoric toward the North, threatening, for instance, "fire and fury" toward the country.

Pyongyang will "seriously consider" countermeasures against the drill, and the US and South Korea will "pay dearly for their provocations", the Korean Central News Agency said before the start of the exercises.

While many South Koreans typically ignore North Korea's rhetoric, some senior American officials have expressed worry following the ICBM test, North Korea's third.

Republican Senator Lindsey Graham said he believes it's time for US military families in South Korea to leave the country because conflict with North Korea is getting close.

The US Government has not announced a formal decision to evacuate US citizens from South Korea, and there were no such signs in the diplomatic community in Seoul. An evacuation of dependents by Seoul's closest ally and major military defender could prompt a panicked reaction by other countries, and among South Koreans.

In addition to American diplomats and other embassy workers, about 28,500 US troops operate in South Korea, and many come to their posts with their families, who often live on huge, well-guarded military bases.

Meanwhile, the White House national security adviser has said that Trump will take care of North Korean threats by "doing more ourselves". "The priorities that the President's given us to move as quickly as we can to resolve this crisis with North Korea," General H.R. McMaster told Fox News in an interview.

"If necessary, the President and the United States will have to take care of it, because he has said he's not going to allow this murderous, rogue regime to threaten the United States."