The flight came after days of increasingly bellicose rhetoric between US President Donald Trump and North Korean leader Kim Jong-Un's regime, as international alarm mounts over Pyongyang's nuclear ambitions.
US bombers have carried out similar show of force flights as the United States and the international community struggle to rein in North Korea's weapons programs.
But this was the furthest north of the Demilitarized Zone (DMZ) any US fighter or bomber aircraft has flown off North Korea's coast in this century, Pentagon spokeswoman Dana White said.
"We are prepared to use the full range of military capabilities to defend the US homeland and our allies."
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The Air Force B-1B Lancer bombers used today are based in Guam, and were accompanied by F-15C Eagle fighter escorts from Okinawa, Japan, White said.
A shallow 3.5-magnitude earthquake that hit North Korea near its nuclear test site today was likely an aftershock from the hermit state's latest nuclear test on September 3, a nuclear test ban watchdog and other experts said.
The North, which says it needs nuclear weapons to protect itself against the threat of a US invasion, responded yesterday with a rare personal rebuke from Kim, who called Trump "mentally deranged" and threatened the "highest level of hard-line countermeasure in history.