The temblor was felt at the site of a massive landslide in northern Taiwan but did not hamper rescue efforts. The 6.5-magnitude quake hit at 10:59 a.m., 295 km off the southern Taiwan city of Taitung at a depth of 10 km, the US Geological Survey said.

The agency's initial report had put the quake's magnitude at 6.9. In Taipei, buildings swayed for up to 20 seconds when the quake hit, but police said there were no reports of casualties or damage anywhere on the island. No tsunami alert was issued.

In northern Keelung county, 30 km northeast of Taipei, the tremor caused little new damage at the site of a massive landslide, police said.

On Sunday, a hillside collapsed onto a three-lane highway following several days of rain, burying three cars.

Many of the hundreds of workers digging through the rubble felt the temblor but went on searching for the four passengers believed to have been buried in the cars, police said.

Earthquakes frequently rattle Taiwan but most are minor and cause little or no damage.

However, a 7.6-magnitude earthquake in central Taiwan in 1999 killed more than 2,300 people.