MANILA — A typhoon packing winds of nearly 100 miles per hour made landfall in the eastern Philippines on Thursday after gathering strength as it swept across the Pacific Ocean, the state weather bureau said.

Typhoon Vongfong was traveling slowly westward at about 10 m.p.h. when it made landfall at 12:15 in the province of Northern Samar in the eastern Philippines, according to the Philippine Atmospheric Geophysical and Astronomical Services Administration.

Forecasters predicted that it could dump torrential rains by Saturday across a wide area of the Philippines, including possibly Luzon, the country’s largest island, which has a population of 60 million and includes the capital, Manila.

Much of Luzon remains on lockdown because of the coronavirus epidemic, which could complicate emergency efforts should the storm strike the island with particular force.

“Definitely this is going to add to our emergency situation,” said Harry Roque, a spokesman for President Rodrigo Duterte. “While the areas expected to be hit by the typhoon are not heavily ravaged by Covid-19, we have set some guidelines.”

He said that any families taken to evacuation areas would have to observe strict social distancing guidelines. But judging from evacuations during previous typhoons, he conceded that “enforcing that would be a challenge.”

The country’s civil defense office said the storm could cause some damage to houses made of light materials, and it advised those living along shorelines to move to evacuation shelters.

Weather officials said the storm was gathering force on Thursday. The place where it made landfall, San Policarpo, is a city of more than 14,000 people on the northeast of the island of Samar. There were no immediate reports of deaths or injuries.