A magnitude-6.7 earthquake striking Japan's northeastern region late Tuesday left at least 26 people injured with thousands forced to take shelter at evacuation centers, officials said Wednesday.

According to the Fire and Disaster Management Agency, of those injured, seventeen were in the hardest-hit region of Yamagata, four were in Niigata and Miyagi prefectures and another in Ishikawa prefecture.

The powerful quake struck at 10:22 p.m. local time on Tuesday at a depth of about 14 km.

Its epicenter was located off Yamagata and the quake caused a tsunami warning to be issued which was lifted hours later, the Japan Meteorological Agency said (JMA).

In the city of Niigata a 10-cm tsunami was observed, the weather agency said, and smaller ones were recorded at other seafront locations including Sakata and Wajima cities.

The temblor registered upper 6 on Japan's seismic intensity scale which peaks at 7 in Murakami in Niigata.

Thousands of people in the city and surrounding regions had to take shelter at temporary evacuation centers, local officials said.

In one local school gymnasium in the city, around 200 people comprising young and elderly people had rushed to the safety of the building after the quake struck.

Others in the area had evacuated from trains and headed for higher ground fearing a large tsunami might strike and engulf the area.

The quake caused a number of landslides in Tsuruoka, the Yamagata prefectural government said, and soil liquefaction in the area caused some vehicles to be trapped in the mud.

In Niigata and Yamagata prefectures, the quake caused a blackout affecting more than 9,000 homes, but electricity services were restored by 6:44 a.m., Tohoku Electric Power Co. said.

Railway operator East Japan Railway Co. said that Shinkansen bullet train operations were delayed Tuesday as a result of the quake with around 10,000 passengers delayed.

Train schedules returned to normal as of Wednesday, the operator said.

Airline companies said that flights to and from the regions hit by the quake would not affect flight scheduling on Wednesday.

The weather agency said the quake might cause more landslides and warned that houses could possibly collapse. It said that earthquakes of a similar magnitude could strike northeastern regions like Yamagata and Niigata prefectures facing the Sea of Japan over the next week.