Death toll from earthquake in southwestern Japan rises to 35

The death toll from the powerful earthquake that struck Japan's southwestern Kumamoto prefecture on Kyushu Island on Tuesday has risen to 35, prefectural officials said Friday.

However, it has not yet been confirmed whether all of the deaths can be directly attributed to the earthquake, public broadcaster NHK reported.

The death toll could rise further as the search for survivors continues.

The critical 72-hour rescue window expires Friday afternoon.

The Japan Meteorological Agency measured Tuesday's earthquake at magnitude 7.1, while the US Geological Survey (USGS) and Germany's GEOFON seismic monitoring network estimated it at 6.8.

The quake registered a maximum 7 on Japan's seismic intensity scale, the highest level.

The tremor struck at a depth of 10 kilometers (6.2 miles) at 4.27 pm local time (0727 GMT), about 5 kilometers (3.1 miles) east of Uto in Kumamoto Prefecture, according to the USGS.

Hundreds of smaller earthquakes have occurred since the main shock.

In Hikawa Town, which has a population of around 10,000, more than 120 houses and other buildings were completely destroyed.

In Kashima Town, about 20 kilometers (12.4 miles) away, rescue operations at the Aeon Mall Kumamoto shopping center continue.

The mall was severely damaged by an explosion, believed to have been caused by a gas leak, about 80 minutes after the earthquake.

Seven people rescued from the site have died, while five of them are injured.

The exact cause of the explosion has not yet been determined.

At another heavily damaged site, a smokestack collapsed at the Nippon Paper Industries plant in Yatsushiro City.

Eleven people trapped at the facility were rescued, nine of whom died.

Japan, one of the world's most earthquake-prone countries, lies along the Pacific "Ring of Fire" and experiences about 20% of the world's earthquakes measuring magnitude 6.0 or greater.