The air force drills were part of the ongoing South Korea-US Ulchi Freedom Shield and Warrior Shield field exercises that kicked off on August 21, the ministry added.
The B-1B accompanied F-16 jets, deployed by the US, and South Korea's F-50 fighters. The ministry did not specify the number of aircraft involved in the exercise.
"This exercise demonstrated solid combined defense capabilities and the activation of extended deterrence procedures through the timely coordination and deployment of US strategic assets in response to North Korea's recent launch of an alleged ballistic missile," the ministry said in a statement, adding that this was the tenth such drill.
On August 24, North Korea officially announced the failure of a second attempt to launch a military reconnaissance satellite and said it would attempt a third launch in October.