Hong Kong, China (CNN) -- Typhoon Megi cut a deadly path into Asia on Friday, triggering mudslides that killed seven people and trapped more than 400 others in automobiles in Taiwan, officials said.

At least 23 people, including 19 passengers on a tour bus, remained missing Friday night, Taiwan's official Central News Agency reported.

Rescuers were searching for the missing and providing food to other stranded tourists trapped in the mountainous region of northeastern Taiwan.

Helicopters were able to evacuate about 70 people, China's state-run Xinhua news agency reported.

The driver and a passenger of a second tour bus were also listed as missing Friday after their vehicle was buried by a landslide, CNA reported.

Soldiers were deployed to rescue those trapped, including about 200 visitors from China, said Cai Min, a spokesman for Taiwan's National Disaster Prevention and Protection Commission. More than two dozen travelers had been rescued by late afternoon Friday, officials said.

The rock slides happened mainly along the Suhua Highway, in northeast Taiwan, Cai said.

Megi, which killed at least 11 people in the Philippines, is expected to reach the Asian continent in southern China early Saturday, according to the Hong Kong Observatory.

On the streets of Hong Kong, there were no signs of the typhoon yet.

"Although it is difficult to predict Megi's exact track, the public should stay alert and attend to their personal safety. They should stay away from the shoreline, avoid unnecessary outdoor activities and ensure drains are not blocked," acting Secretary for Security Lai Tung-kwok said.

As precautions, crews in Hong Kong were deployed to pile sandbags, inspect and trim trees and check drains. Temporary shelters were being opened, and myriad boats were moored.

Megi may be the strongest typhoon to hit China this year, the state-run Xinhua news agency has said.

In southern China, strong gales arrived ahead of Megi. Domestic and international flights have been cancelled, and ferry services have been suspended in Guangdong, Fujian and Hainan, state-run China Daily said.

In Guangdong, crews have fanned out to inspect reservoirs, dikes and water-conservation projects, in an effort to prevent storm-related injuries and deaths.

Nearly 130,000 fishing boats have been recalled in Fujian, Guangdong and Hainan provinces, and more than 150,000 people have fled for safety in Fujian, according to Xinhua.

Officials have issued the highest of four warnings, bracing for possible devastation in coastal areas, Xinhua said. The warning allows local officials six hours to evacuate residents, close schools and airports, and recall vessels that are considered at risk.

On Thursday in the Philippines, lawmakers placed the province of Pangasinan under a state of emergency, to help municipalities recover from Megi, which was known in the Philippines as Typhoon Juan.

The typhoon affected an estimated 258,844 Filipinos, leaving thousands homeless.

CNN's Helena Hong contributed to this report.