United States : A "super typhoon" with the force of a category-five hurricane tore through the US Pacific territories of Northern Marianas and Guam on Monday, with authorities saying they had received reports of "major" damage on the small island of Rota.

The National Weather Service (NWS) said that the "entirety" of Rota was in the eye of Super Typhoon Bavi, with winds of up to 180 miles (290 kilometers) per hour before moving "ever so slowly away" westwards.

But the group of islands - several thousand kilometres (miles) west of the mainland United States - was by midday still being buffeted by fierce winds and driving rain that left residents holed up indoors.

When the storm first hit early Monday, the NWS urged Rota's roughly 1,500 residents on X to "treat these imminent extreme winds as if a tornado was approaching and move immediately to an interior room or shelter NOW!"

Local authorities on Rota -- the southernmost part of the Northern Marianas, less than 80 km (50 miles) north of Guam -- said they had received reports of "major damages", but with communications difficult the extent was unclear.

"We are hanging in there. We are experiencing heavy winds and flooding here... Some people are already reporting major damages," the Rota Municipal Operations Center's public information officer Lou Rosario said.

Rosario added that some cellphone services were down because of a fallen tower.

Previously, the NWS had warned that a direct hit on Rota would make most of the island "uninhabitable for weeks, perhaps longer" with nearly all trees snapped and power outages for "weeks to possibly months".

The island of Tinian, northern parts of Guam and the southern tip of Saipan experienced winds equivalent to a category-one hurricane, NWS meteorologist Marcus Landon Aydlett told a briefing on Facebook Live.

"Super Typhoon Bavi is leaving the area," he said. "Gradually, conditions are going to be improving."

The Northern Marianas and the nearby separate US territory of Guam are collectively home to around 210,000 people.

Authorities on Guam had said the island could see eight to 12 inches (20 to 30 centimeters) of precipitation, resulting in potential flash flooding.

The NWS said that winds of 50-80 mph and gusts of 100 mph were expected to last through late afternoon.

"Residents should remain sheltered in place. NWS continues to describe this as an extremely dangerous and life-threatening situation," it said.

Edwin Santa Theresa, a 56-year-old health clinic worker on Tinian, said that residents were "prepared" for the storm.

"I think our main problem will be fuel because the supply is limited," he told AFP.

"Our power was only restored to my house four days ago (from a previous typhoon in April), but now it's out again. I just hope that after this typhoon passes, electricity will be restored quickly."

Rowell Mariano, 61, in Saipan, the main island of the Northern Marianas, also said that the April storm was worse for him.

"(Super Typhoon) Sinlaku was stronger because the center of the storm passed directly over Saipan," he said.

"During Sinlaku, our house was flooded because of the strong winds and heavy rain, and our ceiling was damaged. Sinlaku was really traumatic for us."

In 2023, another massive storm, Mawar, the biggest in decades, did huge damage in the area.

- 'It hurts' -

Several hundred people were holed up at the Guam Plaza Hotel as the windows shook violently and rain leaked into rooms and stairwells.

Around 70 percent of people staying in the hotel - which in April spent $800,000 on a backup generator - were locals who had moved in while the storm passes.

"Our hotel is locally owned so we cater to our local customers and we are going to make sure they have a shelter here," general manager Sudipta Basu, 59, told AFP.

Already on Sunday afternoon, the roads of Guam and the Northern Marianas were practically deserted except for police cars and surfers driving back from enjoying the huge waves. Almost all stores were closed, many of them with their windows boarded up.

Pinky Cubacub, 55, said she bought $500 worth of plywood at a lumber store for her eatery on Guam.

"I cannot afford to lose so many days. It hurts," she told AFP.

- El Nino -

The world's oceans experienced their hottest June on record and could set fresh highs in the months ahead, the European Union's Copernicus Marine Service said on Wednesday.

Warmer oceans help tropical storms to intensify and add more moisture, which can fall as heavy rain.

The World Meteorological Organization warned on Friday that El Nino, which typically occurs every two to seven years and lasts nine to 12 months, has already begun in the tropical Pacific and is likely to be strong.

The natural climate phenomenon warms surface temperatures in the central and eastern equatorial Pacific Ocean, bringing worldwide changes in winds, pressure and rainfall patterns.

"Our big concern for this being an El Nino year is that it's going to be a lot busier than we've seen in the last five or six years," said Aydlett of the NWS.