South Korea’s military said in a statement the ongoing drills with the US would end on Friday, not August 27 as initially planned. It said the allies also agreed to downsize some joint field training exercises.

The allies will complete the first, defensive phase of the exercise this week and cancel the second phase involving counter-attack operations, according to local media.

Ulchi is largely a computer-simulated command post exercise meant to hone the allies’ ability to deal with potential regional security threats like North Korean aggression. The two countries usually hold field training exercises during the command post exercise period.