SEOUL, South Korea — North Korea today fired four banned ballistic missiles that flew about 620 miles on average, with three of them landing in waters that Japan claims as its exclusive economic zone, South Korean and Japanese officials said. The test-launches appeared to be a reaction to huge U.S.-South Korean military drills that those countries consider routine but that Pyongyang insists are an invasion rehearsal.

It was not immediately clear the exact type of missile fired, but the tests will be viewed as a provocation by the Trump administration, which is working on its policy for North Korea. The New York Times reported over the weekend that the United States still can’t effectively counter Pyongyang’s actions despite efforts to perfect cyber and electronic strikes against North Korea’s missile program.

Pyongyang has test-launched a series of missiles of various ranges in recent months, including a new intermediate-range missile in February; it also conducted two nuclear tests last year. The ramped-up tests come as leader Kim Jong Un pushes for a nuclear and missile program that can deter what he calls U.S. and South Korean hostility toward the North.

There have been widespread worries that the North will conduct an ICBM test that, when perfected, could in theory reach the U.S. mainland. Washington would consider such a capability a major threat.

U.S. National Security Adviser H.R. McMaster and his South Korean counterpart Kim Kwan-jin talked by phone after the missile firings. The two condemned the launches and agreed to boost cooperation to get the North to face more effective sanctions and pressure, according to South Korea’s presidential office.

Japanese Prime Minister Shinzo Abe said three missiles landed in the 200-nautical-mile offshore area where Tokyo has sovereign rights for exploring and exploiting resources. He said a fourth missile fell “near” Japan’s exclusive economic zone.