IZUMI, Japan (AFP) — Millions of people in Japan were under evacuation warnings on Monday as Typhoon "Nanmadol" brought strong winds and heavy rain to the southwest of the country after making landfall overnight.

The powerful system has weakened since arriving on land Sunday evening around Kagoshima city in the southwestern region of Kyushu, but it has still uprooted trees, smashed windows and left rivers close to overflowing.

National broadcaster NHK said one person had been killed and 50 others injured as the storm passed through Kyushu. There was no immediate confirmation of the figures from authorities.

Prime Minister Fumio Kishida, who had been scheduled to leave Monday for the United Nations General Assembly, will delay his trip by a day to check on damage from the storm, his office confirmed.

Officials from the Japan Meteorological Agency warned that in Miyazaki prefecture, where some areas saw more rainfall in 24 hours than they normally receive in all of September, river levels were high.

"Even a tiny amount of additional rainfall could cause the water level to increase, so please remain vigilant about flooding and landslides," Yoshiyuki Toyoguchi from the land ministry told reporters.

Still, given the intensity of the storm, which came ashore packing gusts of up to 234 kilometers an hour, damage appeared relatively limited so far.

"The typhoon has all but disappeared today and the rain and wind are also subsiding now," an official in charge of crisis management in Miyazaki's Saito city told AFP.

"But power is out in some places… we're also hearing from many residents that electrical wires have been severed and trees have been toppled," he said, declining to be named.

"Flooding is affecting some areas as well," he added, saying that officials "believe there are still many details of the damage we're yet to grasp."

Rare "special warnings" for Kagoshima and Miyazaki prefectures, issued only when weather events seen every few decades are forecast, have been downgraded.

But evacuation warnings of various levels remained in place for 9.6 million people on the last day of a holiday weekend in Japan.

The warnings are not mandatory, and authorities have at times struggled to convince residents to leave their homes during extreme weather events.

No power

By Monday morning, nearly 313,000 households in Kyushu and neighboring Chugoku region were without power, utilities said. Hundreds of flights had been cancelled, NHK said, and many train services throughout the affected regions were also halted.

As of 11:00 a.m., the typhoon was spiraling north-northeast near Kitakyushu, Kyushu island's northernmost city, with maximum gusts of around 162 kilometers per hour, according to the JMA.

"The thick cloud and eye area around the typhoon's center have already disappeared and it is weakening rapidly," Ryuta Kurora, the head of the JMA's forecast unit, told reporters.

"The typhoon is still weakening, and from 9:00 a.m. it has been downgraded from a category strong and large typhoon to a large typhoon," he said.