At least 30 people were killed after a powerful earthquake hit Japan on New Year’s Day, with rescue teams on Tuesday struggling to reach isolated areas where buildings had been toppled, roads wrecked and power cut to tens of thousands of homes.

The quake with a preliminary magnitude of 7.6 struck in the middle of the afternoon on Monday, prompting residents in some coastal areas to flee to higher ground as tsunami waves hit Japan’s west coast, sweeping some cars and houses into the sea.

Thousands of army personnel, firefighters and police officers from across the country have been dispatched to the worst-hit area in the Noto peninsula in Ishikawa prefecture.

However, rescue efforts have been hindered by badly damaged and blocked roads and authorities say they are finding it difficult to assess the full extent of the fallout.

Many rail services, ferries and flights into the area have been suspended. Noto airport has closed due to damage to its runway, terminal and access roads, with 500 people stranded inside cars in its parking lot, according to public broadcaster NHK.

“The search and rescue of those impacted by the quake is a battle against time,” Prime Minister Fumio Kishida said during an emergency disaster meeting on Tuesday.

Kishida said rescuers were finding it very difficult to reach the northern tip of the Noto peninsula due to wrecked roads, and that helicopter surveys had discovered many fires and widespread damage to buildings and infrastructure.

Authorities in Ishikawa said they had confirmed 30 deaths from the earthquake so far, with half of those fatalities in hard-hit Wajima city near the quake’s epicentre.

Firefighters have been battling blazes in several cities and trying to free more people trapped in collapsed buildings, Japan’s fire and disaster management agency said.

More than 140 tremors have been detected since the quake first hit on Monday, according to the Japan Meteorological Agency. The agency has warned more strong shocks could hit in the coming days.

The Japanese government ordered around 100,000 people to evacuate their homes on Monday night, sending them to sports halls and school gymnasiums, commonly used as evacuation centres in emergencies.

Many returned to their homes on Tuesday as authorities lifted tsunami warnings.

But around 33,000 households remained without power in Ishikawa prefecture early on Tuesday morning after a night where temperatures dropped below freezing, according to Hokuriku Electric Power’s website. Most areas in the northern Noto peninsula also have no water supply, NHK reported.

The quake comes at a sensitive time for Japan’s nuclear industry, which has faced fierce opposition from some locals since the 2011 earthquake and tsunami that triggered nuclear meltdowns in Fukushima. Whole towns were devastated in that disaster.

Japan last week lifted an operational ban imposed on the world’s biggest nuclear plant, Kashiwazaki-Kariwa, which has been offline since the 2011 tsunami.

The Nuclear Regulation Authority said no irregularities were found at nuclear plants along the Sea of Japan, including five active reactors at Kansai Electric Power’s (9503.T) Ohi and Takahama plants in Fukui Prefecture.