Taiwan has been struckby its strongest earthquake in 25 years on Wednesday, a 7.4 magnitude tremor that shook the island’s eastern coast, bringing down multiple buildings, triggering landslides and killing at least four people.

The quake hit at 7:58 a.m. local time 18 kilometers (11 miles) south of Hualien city and at a depth of 34.8 kilometers (21 miles), according to the US Geological Survey. It was followed by several strong aftershocks with tremors felt across the island.

Taiwan’s National Fire Agency said at least four people were killed and 57 others injured in the quake. The deaths occurred in Hualien County, with a hiker among those killed. Officials were still gathering information on casualties, the NFA said.

Reports of extensive damage have also emerged, with people trapped in collapsed buildings in Hualien County, thousands of homes left without power and a major highway along the east coast shut to traffic due to landslides and rockfalls, according to Taiwanese officials.

Taiwan’s Central Weather Administration spokesperson warned that powerful aftershocks as high as magnitude 7 are expected to occur until the end of the week.

The quake prompted initial tsunami warnings in Taiwan, southern Japan and the Philippines, with waves less than half a meter observed along some coasts, and prompting airlines to suspend flights. However, all tsunami warnings were later lifted.

In Taiwan, military personnel have been dispatched to help with disaster relief and schools and workplaces suspended operations as aftershocks hit the island, according to the Defense Ministry.

Taiwan’s outgoing President Tsai Ing-wen said Wednesday she had ordered her administration to “immediately” get “on top of the situation and understand local impacts as soon as possible.”

Tsai also told the administration to “provide necessary assistance, and work together with local governments to minimize the impact of the disaster.”

Taiwan is regularly rocked by earthquakes due to its location on the Pacific Ring of Fire, which runs around the edge of the Pacific Ocean and causes massive seismic and volcanic activity from Indonesia to Chile.

Wednesday’s quake is the strongest to hit Taiwan since 1999, according to the Central Weather Administration. That powerful 7.7 magnitude quake hit 93 miles (150 kilometers) south of Taipei, killing 2,400 people and injuring 10,000 others.