On Tuesday, a South Korean lawmaker said North Korean hackers had reportedly stolen a large cache of military documents from his country, including a wartime contingency plans drawn up by the USA and South Korea.
If confirmed, such a hack would be a major blow for South Korea at a time when its relations with North Korea are at a low point.
The exercises came hours after a South Korean lawmaker claimed North Korean hackers had stolen a large cache of military documents from his country, "including a plan to assassinate North Korea's leader Kim Jong Un, and wartime contingency plans drawn up by the United States and South Korea", reports the BBC. The South Korean defence ministry has so far refused to comment on the breach, which reportedly dates back to last September.
Rhee told CNN on Tuesday that the documents stolen included the South Korea-US wartime operational plan and a document that includes procedures to "decapitate" the North Korean leadership.
"If I had access to the enemy's plans, not only would I know what forces were going to be arrayed against me, I would know where they will be, what weapons they will have, where the command and control nodes will be established - all critical war-fighting information".
This comes after US President Donald Trump last night discussed a "range of options" with his national security team to respond to North Korea's recent nuclear tests.
It was part of a "regular deployment training" aimed at enhancing the capability of implementing the "extended deterrence" against the North, the JCS said.
The warplanes first conducted a simulated air-to-ground missile drill over the waters east of the Korean Peninsula and then flew over South Korea and conducted the same drill over the waters west of the peninsula, the South Korean military said.
According to South Korea's Joint Chiefs of Staff in a statement on Wednesday, the two U.S. Air Force B-1B bombers were joined by two F-15K fighters from the South Korean military after leaving their base in Guam.
The drills were conducted not long after Lee broke the news about the alleged cyberattacks to reporters.
Reports of reconnaissance on U.S. utilities follow earlier reports alleging DPRK spies stole a large cache of military documents from South Korea, including a plan to assassinate North Korea's leader, Kim Jong-un.
A pre-emptive strike against Pyongyang's leadership would be hard to undertake, but it's widely seen as the most realistic of the limited military options Seoul has to deny a nuclear attack from its rival. He revealed that around 235 gigabytes of military documents had been stolen from the Defence Integrated Data Centre, and that 80% of them have yet to be identified.
Seoul says North Korea has repeatedly staged cyberattacks on South Korean business and government websites.
There is no evidence that the attacks were successful, and cybersecurity experts believe that North Korea lacks the ability to disrupt the power grid.
North Korea has yet to comment on either the bombing drills or the hacking claims.