Tokyo ? A strong earthquake rocked northeastern Japan late Wednesday, shaking buildings in Tokyo and nearby areas and briefly shutting down train lines. Two people were reportedly injured.

The earthquake, with a preliminary magnitude of 6.5, was centered 30 miles below the sea off the coast of Ibaraki prefecture, about 70 miles northeast of Tokyo, the U.S. Geological Survey said. There was no danger of a tsunami, officials said.

The quake shook 20 of the country’s 47 prefectures, said Takeshi Hachimine, a spokesman for Japan’s Meteorogical Agency. He said the region should brace for aftershocks measuring at least magnitude 5.0 over the next few days.

A woman in Ibaraki cut her nose after falling out of her bed, while another slightly injured her hip near Tokyo, according to the Kyodo News agency. Police spokesman Meihan Toyoshima said no serious injuries had been reported.