Typhoon Rai destroyed the southern and central portions of the archipelago, knocking out communications and electricity in many locations, ripping off roofs, and toppling concrete power poles, forcing more than 300,000 people to flee their homes and beachside resorts.

When Rai slammed into the renowned tourist island of Siargao on Thursday, it was a super typhoon with maximum sustained winds of 195 kilometers per hour (120 miles per hour).

"This is indeed one of the most powerful storms that have hit the Philippines in the month of December in the last decade," Alberto Bocanegra, head of the International Federation of Red Cross and Red Crescent Societies in the Philippines, told AFP.

"The information we are receiving and the pictures we are receiving are very alarming."

According to Mark Timbal, Spokesperson for the National Disaster Agency, more than 18,000 military, police, coast guard, and fire personnel will join search and rescue efforts in the worst-affected areas.

"There has been severe damage" on Siargao Island and the northern tip of the southern island of Mindanao, Timbal said, referring to areas that bore the brunt of the typhoon as it slammed into the country.

There are around 100,000 residents on Siargao, but the population swells with visiting surfers and holidaymakers. Surigao City Mayor Ernesto Matugas told broadcaster ABS-CBN that the death toll reached 21.

The vice governor of Dinagat, an island near Siargao, said at least six people had been killed there.

Update

At least 33 people were killed in the strongest typhoon to hit the Philippines this year with dozens more missing after the storm ravaged the country, state officials declared on Saturday.

The latest figures come after a disaster official in the central province of Negros Occidental confirmed 13 people had died, most by drowning, and that another 50 were missing in a flood-hit area.