A strong earthquake shook Tokyo and other cities in eastern Japan on Monday, but officials said there is no danger of a tsunami.
The Meteorological Agency said the earthquake had an initial magnitude of 5.6 and was centered in southern Ibaraki prefecture, about 100 kilometers (60 miles) northeast of Tokyo.
The agency said the earthquake was located about 40 kilometers (24 miles) underground, and there was no danger of a tsunami. There were no immediate reports of injuries or damage.
The earthquake also shook Tsukuba, where science and technology ministers from the Group of Seven nations are meeting.
"There were strong vertical motions, but nothing fell to the floor or broke," Hiroyuki Oseki, a disaster management official for the Ibaraki prefectural government, said in a telephone interview with NHK public television. He said he was inside the prefectural government building when the earthquake hit.
Local trains were temporarily halted for safety checks.
The quake came a month after two strong earthquakes struck Kumamoto prefecture in southern Japan, leaving 49 people dead and destroying many houses. Thousands of people are still staying in schools, community centers and other shelters, while others are living in their cars -- a situation which experts say raises risks of health problems from a lack of exercise and fresh foods.