TOKYO, March 22 (UPI) -- A 6.6-magnitude earthquake hit Japan Tuesday, the third strong aftershock in 2 1/2 hours near the epicenter of the March 11 mega quake, scientists said.
The U.S. Geological Survey said the two other quakes had preliminary magnitudes of 6.6 and 6.4, making them among the strongest of several temblors that have rocked northeastern Japan since the 9-magnitude earthquake and tsunami struck.
Japan's National Police Agency said as of 6 p.m. Tuesday the death toll from the March 11 quake had reach 9,080 in 12 prefectures with 13,561 missing, Kyodo News reported.
The Ministry of Education, Culture, Sports, Science and Technology said 5,682 schools in 23 prefectures were damaged, while classes at 3,379 schools in 16 prefectures have been suspended.
The government also said 270,000 evacuees are living in about 1,900 shelters spread across 16 prefectures.
East Japan Railway Co. said it had resumed bullet train services between Morioka and Shin-Aomori stations. The Tohoku Expressway, a major route between Tokyo and the quake-hit region, was reopened to trucks.
Tokyo Electric Power Co. said Tuesday all six reactors at the quake-stricken Fukushima Daiichi nuclear power plant have been reconnected to external power, Kyodo News reported. The plant operator said it had restored lighting in the control room for the No. 3 reactor, which was expected to facilitate efforts to restore the reactors' cooling functions.
"I think the situation will head toward a better direction, but it is too early to say that things have stabilized sufficiently," Kyodo quoted Tokyo Electric Executive Vice President Sakae Muto as saying.
Hidehiko Nishiyama, spokesman of the government's nuclear safety agency, told reporters getting electricity into the facilities would allow crews to check whether the current measures being taken are adequate to contain the crisis.
He said a critical full-scale "meltdown" was unlikely, Kyodo said.
TEPCO executives apologized in person for the first time since the quake, Kyodo said.
Operations had been suspended Monday when smoke was detected at the Nos. 2 and 3 reactors, the plant's operator said.
Firefighters and TEPCO crews sprayed huge amounts of water onto the spent nuclear fuel pools at the No. 3 and No. 4 reactors.
While white smoke -- identified as possibly steam -- spewed from the buildings housing the No. 2 and No. 3 reactors, but TEPCO officials said the smoke didn't hinder work to restore electricity and radiation levels did not surge at the site.
After the earthquake and a subsequent tsunami knocked out power at the plant, cooling functions failed at the Nos. 1, 2 and 3 reactors and their cores were believed to have melted partially. Pools storing spent nuclear fuel rods outside reactors at the Nos. 2, 3 and 4 units lost their cooling capabilities, requiring water to be pumped in. Hydrogen explosions blew off the roofs and upper walls of the buildings housing the Nos. 1, 3 and 4 units.
Japanese Economy, Trade and Industry Minister Banri Kaieda said during a news conference Tuesday the situation remains "extremely tough."
"It is difficult to say that things are showing progress from my feeling," Kaieda said.
Tokyo Electric resumed its rolling blackouts Tuesday after a long weekend, with demand for electricity expected to exceed its quake-affected supply capacity, Kyodo reported.
TEPCO officials Tuesday confirmed seawater pollution near the plant has expanded, one day after concentrated radioactive substances were detected in seawater near the plant's water discharging outlets. Nuclear safety agency officials said the substances, such as iodine and cesium, don't pose immediate health threats, Kyodo reported.
Tokyo Power also planned to test Pacific Ocean water samples from four locations off the plant, after finding highly concentrated radioactive substances in the seawater near the plant's water discharging outlets.
As concerns rise about radiation contamination of food items, the Japanese government ordered Fukushima and three other prefectures to suspend shipments of spinach and another leaf vegetable, kalina, after radioactive substances were found in the produce. Trace amounts of radioactive substances also were detected in drinking water in nine prefectures, but not at unsafe levels.
The World Health Organization has said it is watching the food contamination situation but noted there didn't appear to be any immediate health risk.