The South Korean and U.S. militaries conducted large live-fire drills near the border with North Korea on Thursday, despite the North’s warning that it won’t tolerate what it calls an invasion rehearsal on its doorstep.

The drills, the first of five rounds of live-fire exercises through mid-June, mark 70 years since the establishment of the military alliance between Seoul and Washington. North Korea typically reacts to such major South Korean-U.S. exercises with missile and other weapons tests.

Since the start of 2022, North Korea has test-launched more than 100 missiles, but none since it fired a solid-fuel intercontinental ballistic missile in mid-April. It says the tests are a response to expanded military drills between the U.S. and South Korea, but observers say North Korea aims to advance its weapons development and then wrest greater concessions from its rivals in eventual diplomacy.

The U.S.-South Korean firing exercises, called “Combined annihilation firepower drills,” are the biggest of their kind. The drills have been held 11 times since they began in 1977, according to the South Korean Defense Ministry.

The drills involved 2,500 troops and 610 weapons systems such as fighter jets, attack helicopters, drones, tanks and artillery from South Korea and the United States, according to the South Korean Defense Ministry. The most recent exercises in 2017 drew about 2,000 soldiers and 250 weapons assets from both countries.

The drills simulated artillery and aerial strikes on front-line North Korean military facilities in response to an attack. The troops later practiced precision-guided attacks on simulated targets in the rear areas to “completely annihilate” North Korean military threats, according to a ministry statement.

AP