A strong 6.4-magnitude earthquake hit off eastern Taiwan on Saturday evening, the US Geological Survey said, the biggest tremor to rock the island this year.
Buildings were shaking for about 20 seconds in the capital Taipei, in the northern part of the island, but there were no immediate reports of serious casualties or damage anywhere.
"It was the strongest quake to hit Taiwan this year," said Kuo Kai-wen, head of the Seismology Centre at Taiwan's central weather bureau.
"The Japanese authorities have issued a tsunami warning so we urge the public to stay away from the sea," he told reporters.
The Hawaii-based Pacific Tsunami Warning Center did not issue a tsunami alert.
The epicentre of the undersea quake, which occurred at 9:02 pm (1302 GMT), was 25 kilometres (15 miles) southeast of the eastern coastal city of Hualien, according to USGS.
The quake was at a depth of 44.6 kilometres, USGS said.
Taiwan is located in one of the most seismologically active areas of the world and registers a large number of quakes every year.
In Hualien, a number of minor incidents were reported in the minutes after the quake.
"There were gas leaks and minor fires and people trapped in elevators," an official at the Hualien fire department told AFP by telephone. He also reported some damage to roads in Hualien county.
The fire department said ten people had sought medical help after feeling unwell due to a gas leak at a hotel. The number was up from initially three people.
Local TV reported that a high-speed railway linking Taipei to the southern city of Kaohsiung had been suspended as a safety precaution.
Initial reports in local media that a building in the Taipei area had collapsed turned out to be a false alarm, according to radio and the Taipei fire department.
The quake was followed by a 4.7-magnitude aftershock at 9:15 pm, according to the weather bureau.
Taiwan's weather bureau gave the magnitude of the initial quake as magnitude 6.8. The island uses a slightly different scale from USGS.
Explore further: Africa, from a CATS point of view