Some schools in the heavily devastated towns of Ojiya and Nagaoka reopened Monday, 10 days after a series of powerful quakes started pummeling the Chuetsu region in Niigata Prefecture.

The prefectural board of education hopes all schools will resume classes by next Monday at the latest.

The Meteorological Agency has warned of possible magnitude 6 aftershocks for the time being and magnitude 5 aftershocks within a month.

Two quakes measuring preliminary magnitudes of 5.0 and 4.0 hit Niigata early Monday.

At Ojiya Municipal Nishi Senior High School, 223 students, fewer than 40 percent of the school's student body, showed up for classes, some without their uniforms. Many arrived by car because school bus services remain suspended.

Classes also resumed at Nagaoka Meitoku Senior High School, where about 300 evacuees from the village of Yamakoshi are taking shelter in the school gym.

Ojiya Municipal Minami Junior High School has sent teachers to shelters to check on students and follow up on their studies.

The step was taken "because it is a critical period (for third-year students) in the runup to entrance examinations for high schools," said Noboru Toyama, the school's principal.

Three public nursery schools in Ojiya also reopened, with about 20 children showing up.

As of 9 a.m. Monday, 59,668 people were listed as living in temporary shelters, down from a peak of more than 100,000.

As part of reconstruction measures, 16 prefectures had dispatched 55 civil engineers to the quake-stricken areas to survey damage to roads, riverbanks and bridges.

A group of Diet members met with the quake-measure task force of Niigata Prefecture and were briefed on the conditions there before visiting shelters in Nagaoka and other areas.

Yamakoshi, which issued an evacuation advisory to all residents, decided Monday to set up a branch office in Nagaoka City Hall and is expected to begin operations by Friday.