The underground tremors started at 4:06 p.m. local time (07:06 GMT).
At least six houses have collapsed following the seismic activity, Japanese Chief Cabinet Secretary Yoshimasa Hayashi said.
"As of now, six buildings have collapsed, with a possibility of people remaining under the rubble," Hayashi said, adding that the authorities did not possess any information about the injuries.
When asked to comment on the reports in Japanese media about the collapses of around 100 buildings, Hayashi said that the Japanese government was verifying the information.
No disruptions at Japanese nuclear power plants have been reported following a series of strong earthquakes in the country's west on Monday, while the toll of casualties is being tabulated, Chief Cabinet Secretary Yoshimasa Hayashi said.
No emergency reports have been received, in particular, from the Shika nuclear power plants in Ishikawa prefecture, which is believed to be affected by the quake the most, Hayashi said.
The recent earthquake in the Japanese prefecture of Ishikawa has become the strongest on the Noto peninsula since 1885 when record started, the Japan Meteorological Agency (JMA) said on Monday.
"It was the strongest since 1885," JMA representatives told a press conference.
A major tsunami warning issued on Monday following a series of earthquakes in Ishikawa has been the first since 2011, when the Great East Japan Earthquake occurred, the JMA said. Besides that, over 7 magnitude underground tremors have hit Japan for the first time since 2018, the experts said.
A major fire has broken out in the Japanese city of Wajima in the Ishikawa prefecture after a series of the powerful earthquakes, the local media reported on Monday.
Several fire brigades are involved in putting out the fire, Japanese broadcaster reported.
The experts from Japan's Meteorological Agency warned on the possibility of repeated tremors with a magnitude of up to 7.0 within approximately a week after the Monday earthquakes.
“In areas of the strongest tremors observed, the earthquakes of up to seven magnitude are possible for about a week, especially in the next two- three days,” the experts said.
On Monday, a series of strong earthquakes occurred in Japan. A magnitude 5.7 earthquake was recorded at 4:06 p.m. local time, followed by a magnitude 7.6 quake 4 minutes later, and a magnitude 6.1 earthquake 8 minutes after that. The Japanese authorities issued a tsunami warning. Train service was halted. The work to collect data about casualties and damages started shortly after the underground tremors ended.