The quake, which was a relatively shallow 35 km deep, struck at 0613 IST off the coast of Kamchatka peninsula, the agency said.
There was no tsunami warning.
Kamchatka, the Kuril islands and Japan lie on the so-called Pacific Ring of Fire which is among the world's most earthquake-prone regions.
An earthquake measuring 6.8 on the Richter scale hit northern Japan earlier today, injuring more than 100 people.