NEW: Storm expected to move offshore in the afternoon, state news agency says
NEW: Sustained winds are 120 kph, with gusts of 150 kph
Typhoon Nesat, known in the Philippines as Pedring, struck early Tuesday
More than 64,000 people are affected by the typhoon, disaster officials say
A typhoon that left at least 18 people dead and thousands displaced in the Philippines was expected to move offshore Wednesday afternoon, the state-run Philippines News Agency reported early Wednesday.
A baby boy was among the 21 dead after the typhoon slammed into the Philippines on Tuesday, authorities said. Twenty-five other people were injured, according to the National Disaster Risk Reduction and Management Council.
Four people were reported killed in Metro Manila, two in Central Luzon, and one in Catanduanes, the Office of Civil Defense said. Three more were reported injured and four were missing as of Tuesday afternoon.
The storm struck the agricultural provinces of Isabela and Aurora the hardest. But storm alerts were also issued for more than 40 other areas, including metro Manila, the state weather bureau Philippine Atmospheric Geophysical and Astronomical Services Administration said.
Nearly 321,000 people were affected by the typhoon in 29 provinces, the disaster council said. About 79,000 people were receiving assistance at evacuation shelters.
More than 100 people were rescued across the country, the council said, many of them from boats.
In Albay, in southern Luzon, more than 3,000 people were affected, the state-run news agency said early Wednesday.
The storm was centered about 300 kilometers (186 miles) northwest of Baguio City, in northwestern Luzon, the state-run news agency said, citing PAGASA.
As of 6 a.m. Wednesday, PAGASA said, Pedring had maximum sustained winds of 120 kph (75 mph) near the center, with gusts of up to 150 kph (93 mph) and was forecast to move west-northwest at 19 kph.
On Tuesday, weather officials said the storm was packing top winds of 140 kph (87 mph).
The presidential palace announced the suspension of all classes for schools and work for government agencies in Manila and other affected areas. The Philippine Stock Exchange also suspended trading.
Some roads around Manila were impassable due to flooding and falling debris, including branches that had been ripped off trees.
Several areas in Metro Manila and nearby provinces were without electricity as the powerful storm cut power and transmission lines.
DJ Santa Ana, head of news operations at TV5 in Manila, told CNN it was likely to take some time to restore the power supply in major parts of Metro Manila.
Santa Ana said people in the capital remained calm as the rain kept coming down, although one part of eastern Manila had to be evacuated because of flooding.
Between a half-inch to 1 inch of rain an hour is forecast within the 650 km diameter of the typhoon, state forecasters said.
CNN iReporter Sherbien Dacalanio said power was out in some parts of Quezon City for hours. Several restaurants had to close down because of the high winds and many people did not venture out.
Dacalanio said the winds had uprooted street lights and brought down trees and road signs, but that luckily there was no flooding near his home.
Also, Tropical Storm Nalgae was 1,350 km (838 miles) east of northern Luzon, the island where Manila is located, and was expected to enter the Philippine Area of Responsibility within the next 24 hours, the council said in its 3 p.m. Wednesday update.
Journalist Arlene Espiritu contributed to this report