Wellington, New Zealand ? Several real earthquakes hit the geologically unstable Pacific region where scientists were testing a tsunami-warning system – including a powerful one Tuesday north of New Zealand that generated a real tsunami.

There were also three quakes off the coast of Indonesia and two off the remote island nation of Tonga. No damage or injuries were reported.

The latest, a magnitude 5.8 earthquake this morning, rattled Tonga at the same time that emergency authorities on the country’s islands were broadcasting simulated earthquake alerts as part of the Pacific-wide simulation. The quake was the latest in a string of aftershocks to hit the country since a powerful 7.8 quake on May 4. A magnitude 5.1 quake struck Tonga early Tuesday as well.

Tonga’s National Disaster Office deputy director Mali’u Takai said people in the Ha’apai island group near the epicenter of today’s quake felt the ground move as officials were broadcasting mock tsunami warnings.

The National Disaster Office was “bombarded with questions” as the quake hit in the midst of the tsunami test, Takai said. He added that authorities should have done more to make clear to residents that the warnings, broadcast on local radio stations, were part of a test.

The largest quake struck Tuesday north of New Zealand, rocking a wide area of the country. New Zealand national civil defense controller Mike O’Leary said the minor local tsunami it generated did not affect any populated areas.

Later Tuesday night, a magnitude 6.8 earthquake struck western Indonesia.

New Zealand was among more than two dozen countries taking part in the drill to test the Pacific warning system that has been in place since 1965.

During the exercise today, the Pacific Tsunami Warning Center in Hawaii sent out warnings about mock earthquakes off the Chilean coast and Luzon island in the northern Philippines powerful enough to set off a tsunami across the vast ocean.

Governments were testing whether and how fast they receive the warnings and how rapidly they are relayed through domestic emergency alert systems.