COPENHAGEN, Denmark (AP) — A powerful earthquake with a preliminary magnitude of 6.8 struck in the Arctic Ocean Friday, northwest of a largely uninhabited and remote Norwegian island, officials said. No injuries or damage were immediately reported.

The Norwegian earthquake center NORSAR says the quake was recorded at 2:49 a.m. in the sea between the volcanic island of Jan Mayen and Greenland, a Danish territory. The tremor was centered some 120 kilometers (74 miles) off Jan Mayen at a depth of approximately 10 kilometers (6.2 miles), NORSAR said.

Norway's news agency NTB said there were 18 people on the island — military and meteorological institute staff — who were woken by the quake.

Silje Wennesland told NTB that "I had my heart in my throat when I woke up because the mirror and the cabinets shook."

NORSAR said aftershocks are expected but no tsunami warning was issued.

"Fortunately, no one was injured, and everyone is fine, but we noticed it," Wennesland told NTB. "It has happened before, and this was quite powerful," she said, adding the tremor lasted for 30 seconds.

NORSAR said the quake was one of the strongest registered. Since 1970, about 10 quakes have been registered in the region with a magnitude of 6 or higher. The previous such quake was recorded Aug. 30, 2012, and had a magnitude of 6.6.