South Korea and the United States have resumed a joint military exercise after a brief break in the wake of an exchange of artillery fire between the two Koreas, a U.S. official said Friday.

The annual Ulchi Freedom Guardian exercise, which began Monday, "was suspended temporarily, I believe day before yesterday, in order to allow the U.S. side to coordinate with the ROK side on the actual exchange of artillery fire across the DMZ," Assistant Secretary of Defense David Shear told reporters. 

"That exercise has resumed as planned and we are conducting the exercise as planned," he said.

On Thursday, North and South Korea exchanged artillery rounds across their heavily armed border after the North first opened fire in apparent anger over the South's resumption of anti-Pyongyang loudspeaker broadcasts along the border.

"Our commanders need to be briefed on the situation. We need to develop the information and brief our commanders and they need to talk with their ROK counterparts to ensure that we have a mutual understanding of what the situation is," Shear said of the temporary suspension of the exercise.

He also urged the North "to cease provocations across the DMZ and restore calm to the peninsula."

Shear also said that U.S. troops in South Korea are on "enhanced status" to deter the North.

"U.S. forces went on an enhanced status as part of the exercise. They are remaining in an enhanced status as part of the exercise, and of course to ensure adequate deterrence on the peninsula," he said.

The exercise UFG is the world's largest computerized military drill aimed at defending the South from a North Korean attack, involving nearly 80,000 South Korean and U.S. troops. 

North Korea has long condemned such drills as a rehearsal for invasion of the country despite repeated assurances from Seoul and Washington that the exercises are purely defensive in nature.

"We use these exercises to heighten readiness and as a result of the fact that we're conducting this exercise, we are able to communicate and coordinate very efficiently with our ROK partners," Shear said. (Yonhap)