A magnitude 5.8 earthquake Wednesday morning disrupted a simulated tsunami warning drill on the remote South Pacific nation of Tonga, an official said.

The quake rattled Tonga early Wednesday at the same time that emergency authorities on the country's islands were broadcasting simulated alerts as part of a Pacific-wide simulation to test a warning system that spans the world's largest ocean.

CountryWatch: Tonga

The quake, the latest in a string of aftershocks to hit the country since a powerful 7.8 quake on May 4, caused no damage or injury.

Tonga's National Disaster Office deputy director Mali'u Takai said people in the Ha'apai island group near the epicenter of Wednesday's quake felt the ground move as officials were broadcasting mock tsunami warnings, sparking a rash of phone calls to emergency services.