An earthquake with a preliminary magnitude of 6.4 struck in the sea off eastern Russia on Thursday, the U.S. Geological Survey said.

The epicenter of the quake was 41 km (25 miles) east Nikol'skoye, Komandorskiye Ostrova, at a depth of about 10 km (6 miles), the USGS said. There were no immediate tsunami warnings issued after the quake.