"South Korean and US air forces conducted an air interdiction exercise in order to strongly cope with North Korea's repeated firing of ballistic missiles and development of nuclear weapons," the South's air force said in a statement.
Two B-1B "Lancer" bombers from Guam and four F-35B stealth jet fighters from the Marine Corps' Iwakuni airbase in Japan conducted the drill, with four South Korean jet fighters also taking part.
B-1B overflights of the peninsula from Guam, a US territory in the Pacific Ocean, infuriate the North, which condemned the drill on Thursday, the South's Yonhap news agency reported.
"The wild military acts of the enemies are nothing but the rash act of those taken aback" by Pyongyang's latest missile launch, Yonhap cited the official Korean Central News Agency (KCNA) as saying.
Pyongyang had previously announced a plan to fire a salvo of missiles towards Guam.
It was one of the moves that saw tensions spiral this month, along with a new set of UN Security Council sanctions and US President Donald Trump's apocalyptic warning to rain "fire and fury" on Pyongyang, and culminating with the North firing a missile over Japan on Tuesday.
A frustrated Trump took to Twitter to condemn Pyongyang, saying "the US has been talking to North Korea, and paying them extortion money, for 25 years. Talking is not the answer!"
With tensions surging, Moscow urged Washington not to use force against North Korea and also said attempts to toughen sanctions would be counterproductive.
In a phone call late Wednesday with US Secretary of State Rex Tillerson, Foreign Minister Sergei Lavrov "underscored... the need to refrain from any military steps that could have unpredictable consequences," the foreign ministry in Moscow said.
China on Thursday also condemned "destructive" calls for further sanctions, warning Japan, the US and Britain that diplomacy was needed to avert a crisis.
Foreign ministry spokeswoman Hua Chunying said sanctions alone "cannot fundamentally resolve the issue", amid reports the three countries were pushing for new restrictions on North Korean oil imports and foreign workers.
"The current situation on the Korean peninsula is not a screenplay, it's not a computer game. It is a real situation that directly bears on the security of the people on the peninsula and the whole regional peace and tranquility," she said.
Related reading
North Korea and its missiles: what next?
May calls to up pressure
On a visit to Japan on Thursday, British Prime Minister Theresa May said London and Tokyo would work together to pressure North Korea "including by increasing the pace of sanctions" against Pyongyang".
The UN Security Council has already imposed seven sets of sanctions on Pyongyang, the most recent of which were passed this month, but the measures have done little to quell Kim Jong-Un's nuclear missile ambitions.
Thursday's live-fire drill took place at the Pilseung shooting range in Gangwon province, some 150 kilometres (94 miles) south of the Demilitarized Zone dividing the two Koreas.
A South Korean air force spokesman said it was separate from the annual Ulchi Freedom Guardian (UFG) joint exercises, which wrapped up on Thursday.
Tens of thousands of South Korean and US troops took part in the largely computer-simulated exercise that ran for two weeks in the South.
The annual drills are viewed by nuclear-armed Pyongyang as a highly provocative rehearsal for invasion, and it always meets them with threats of strong military counteraction.
A US Forces Korea official told the Yonhap news agency that Washington had avoided sending bombers to the peninsula during the UFG exercises "in hopes that the reduced scale would send a positive signal to North Korea and the region", but Pyongyang had responded with a series of provocations.
The North's state media called Tuesday's Hwasong-12 intermediate range missile flight over northern Japan "a part of the muscle-flexing" against the war games.
Kim Jong-Un called for more launches into the Pacific, the KCNA news agency said.
North Korea says it needs nuclear weapons to protect itself against the US, and analysts say Pyongyang has made rapid strides in its ballistic technology in defiance of seven sets of United Nations resolutions.
In July it conducted two successful ICBM launches which appeared to bring most of the US mainland into range.
