The Maritime and Air self-defense forces kicked off three days of military exercises with two U.S. aircraft carriers in the Sea of Japan on Thursday in a show of force after three missile tests in three weeks by North Korea.

The MSDF’s Hyuga helicopter carrier, one of the larger warships in its fleet, and the destroyer Ashigara joined the USS Ronald Reagan and USS Carl Vinson and their escort ships for the exercises through Saturday, the MSDF said in a statement.

ASDF F-15s from the 6th Air Wing’s Komatsu Air Base in Ishikawa Prefecture were simultaneously taking part in drills with U.S. Navy F-18 fighters. Those exercises were to wrap up Friday.

In a statement posted to its Facebook page, the U.S. Navy’s 7th Fleet said the vessels and aircraft were conducting “routine training to improve interoperability and readiness in the Indo-Asia Pacific.”

In late April, the MSDF conducted drills with the Vinson strike group in the same waters.

This week’s exercises came just after North Korea confirmed Tuesday that it had successfully tested a new “precision-guided” ballistic missile a day earlier, reiterating that it was working to send an even bigger “gift package to the Yankees.” This is believed to be a veiled reference to a long-range missile capable of striking the continental U.S.

The missile flew some 400 km, apparently landing in Japan’s exclusive economic zone in the Sea of Japan — a move that prompted Prime Minister Shinzo Abe to vow “concrete measures” in response. Japan is seeking heavier sanctions against its nuclear-armed neighbor over its repeated missile and nuclear tests in defiance of U.N. resolutions.

On Monday, the North’s state-run Rodong Sinmun daily, quoting a spokesman for the country’s Foreign Ministry, blasted Tokyo’s attempt to pile pressure on Pyongyang.

“Japan incites pressure and sanctions against the DPRK here and there,” the statement said, using the acronym for the North’s formal name, the Democratic People’s Republic of Korea. “It is aimed at providing a legal justification to push ahead with its militarization by cooking up a fascist law at any cost under the pretext of ‘threat’ from the DPRK.”

The spokesman also warned that continued Japanese “hostility” toward the North would result in the country’s missile forces targeting not only U.S. military bases in the country in event of conflict, but the entire nation.

In March, the North conducted what missile experts said was the first overt targeting of U.S. forces in Japan.

“Only the U.S. military objects for aggression in Japan have been within the optical sight of the Strategic Force of the Korean People’s Army,” Monday’s statement said. “But if Japan persists in hostility toward the DPRK, following the U.S. and not properly seeing the reality, the target of the DPRK will be changed.”