TAIPEI -- Two people died and 21 others were injured, including 3 severely, in an earthquake that shook Taiwan's Nantou County on Sunday afternoon, according to the island's disaster response authorities.

The two deaths were reported in Nantou and the neighboring Chiayi County, the authorities said.

One person is still missing, the authorities said.

Zhang Zhijun, head of the Taiwan Affairs Office of the State Council, on Sunday expressed his sympathy in Kunming to the Taiwan compatriots over the earthquake.

Zhang is in Kunming, capital city of southwest China's Yunnan Province, to attend a meeting between Yunnan and Taiwan. He also met there with the Kuomintang (KMT) vice chairman John Chiang.

Also on Sunday, the office's spokeswoman Fan Liqing conveyed condolences to the families of the Taiwanese victims.

She said the mainland's compatriots are deeply concerned about the earthquake and can feel what the Taiwan compatriots feel.

"We are willing to spare no efforts to offer assistance so long as the Taiwan side has need," said Fan.

The epicenter of the 6.7-magnitude earthquake was monitored at about 23.9 degrees north latitude and 120.9 degrees east longitude with a depth of 9 km, according to the mainland's China Earthquake Networks Center.

Taiwan's earthquake authorities measured it at 6.3 magnitude.

As of 6:16 p.m., four smaller-scale aftershocks had been monitored in Nantou, the island's meteorological authorities said.

So far, there have been no reports of deaths or injuries among visitors from the mainland, said Man Hongwei, head of the Taipei office of the Association for Tourism Exchange Across the Taiwan Straits.

Cable-car services in Nantou's Riyuetan (Sun Moon Lake) scenic spot have been halted. But high-speed trains in Taiwan have all restored operations and electricity has been resumed in affected areas, local authorities said.

A 6.1-magnitude earthquake hit Nantou on March 27 this year.

The recent two quakes correlate "a little bit" with a massive earthquake that shook the island nearly 14 years ago, said Lu Pei-ling, an official with the sub-center of Taiwan's earthquake forecasting center.

The 7.3-magnitude quake on Sept. 21, 1999 was the strongest to hit Taiwan in 100 years and left more than 2,000 people dead.

Lu said there is still a possibility that more quakes will occur in this area in the future.