U.S. and South Korea kicked off their annual large-scale springtime exercise, Freedom Shield, on Monday, as North Korea ramped up criticism of the drills as a “war rehearsal.”

This year’s Freedom Shield is scheduled to run from March 10 to 20 and feature 16 field training exercises (FTX) — up from 10 last year — with 19,000 South Korean personnel set to participate.

But the allies have not specified whether the drills, which they describe as defensive in nature, will include scenarios on responding to North Korean nuclear attack, and in a last-minute change, they decided not to conduct live-fire